Search

First, with their study design, the authors are not only comparing two ovarian stimulation strategies but also two completely different settings such as fresh oocyte insemination versus oocyte accumulation via vitrification and fresh versus vitrified-warmed first embryo transfer strategy. Indeed, differences were reported by [3] only in the dual stimulation arm between the two paired cohorts of oocytes, the first cohort being vitrified warmed (e.g. fertilization rate: 66.1%) and the second cohort being fresh (e.g. fertilization rate: 79.7%). Sir, We read with great interest the article 'The BISTIM study: a randomized controlled trial comparing dual ovarian stimulation (Duostim) with two conventional ovarian stimulations in poor ovarian responders undergoing IVF' by [3]. [Extracted from the article]

Objective: To report laboratory and clinical outcomes in preimplantation genetic diagnosis for aneuploidies (PGD-A) cycles for women 44 to 47 years old.Design: Multicenter, longitudinal, observational study.Setting: In vitro fertilization (IVF) centers.Patient(s): One hundred and thirty-seven women aged 44.7 ± 0.7 years (range: 44.0-46.7) undergoing 150 PGD-A cycles during April 2013 to January 2016.Intervention(s): Quantitative polymerase chain reaction-based PGD-A on trophectoderm biopsies and cryopreserved euploid single-embryo transfer (SET).Main Outcomes Measure(s): Primary outcome measure: delivery rate per cycle; secondary outcome measures: miscarriage rate, and the rate and reasons for cycle cancelation with subanalyses for female age and number of metaphase 2 oocytes retrieved.Result(s): In 102 (68.0%) of 150 cycles blastocyst development was obtained, but only 21 (14.0%) were euploid blastocysts. The overall euploidy rate was 11.8% (22 of 187). Twenty-one SET procedures were performed, resulting in 13 clinical pregnancies, of which 1 miscarried and 12 delivered. The delivery rate was 57.1% per transfer, 8.0% per cycle, and 8.8% per patient. The logistic regression analysis found that only female age (odds ratio 0.78) and number of metaphase 2 oocytes retrieved (odds ratio 1.25) statistically significantly correlated with the likelihood of delivery. The delivery rate per cycle was 10.6% (11 of 104) in patients aged 44.0 to 44.9 years and 2.6% in patients aged 45.0 to 45.9 years (n = 1 of 38). No euploid blastocysts were found for patients older than 45.0 years.Conclusion(s): Extensive counseling based on biological and clinical data should be provided to women older than 43 years who are requesting IVF because of their very low odds of success and high risk for embryonic aneuploidies. Nevertheless, the low miscarriage and good delivery rates reported in this study in women with good ovarian reserve aged 44 should encourage the use of PGD-A in this population. [ABSTRACT FROM AUTHOR]

Embryonic mosaicism, defined as the presence of karyotypically distinct cell lines within an embryo, has been frequently reported with a high incidence in preimplantation embryos derived from IVF and is thought to be one of the major biological limitations for the routine application of PGD for aneuploidies (PGD-A). The incidence of mosaicism in preimplantation embryos is in fact reported to be between 4 and 90%. However, these data are in sharp contrast with what is known from clinical pregnancies, where true foetal mosaicism is observed in less than 0.5% of cases. Here, we challenge these previous observations in preimplantation embryos, presenting an alternative perspective, which also considers the impact of technical variation to diagnose mosaicism as one possible cause contributing to overestimation of the incidence of mosaicism in embryos. Although euploid/aneuploid mosaicism may be present in blastocysts, the possibility of detecting this phenomenon within a single trophectoderm biopsy represents a contemporary challenge to bring about improvement to the practice of PGD-A. The purpose of this opinion paper is to provide a critical review of the literature, provide a possible alternative interpretation of the data, and discuss future challenges with diagnosing mosaicism in PGD-A cycles. [ABSTRACT FROM AUTHOR]

Preimplantation genetic diagnosis and aneuploidy testing (PGD/PGS) use is constantly growing in IVF, and embryo/biopsy traceability during the additional laboratory procedures needed is pivotal. An electronic witnessing system (EWS), which showed a significant value in decreasing mismatch occurrence and increasing detection possibilities during standard care IVF, still does not guarantee the same level of efficiency during PGD/PGS cycles. Specifically, EWS cannot follow single embryos throughout the procedure. This is however critical when an unambiguous diagnosis corresponds to each embryo. Failure Mode and Effects Analysis (FMEA) is a proactive method generally adopted to define tools ensuring safety along a procedure. Due to the implementation of a large quantitative PCR (qPCR)-based blastocyst stage PGD/PGS programme in our centre, and to evaluate the potential procedural risks, a FMEA was performed in September 2014. Forty-four failure modes were identified, among which six were given a moderate risk priority number (>15) (RPN; product of estimated occurrence, severity and detection). Specific corrective measures were then introduced and implemented, and a second evaluation performed six months later. The meticulous and careful application of such measures allowed the risks to be decreased along the whole protocol, by reducing their estimated occurrence and/or increasing detection possibilities. [ABSTRACT FROM AUTHOR]

Study Question: Is blastocyst biopsy and quantitative real-time PCR based comprehensive chromosome screening a consistent and reproducible approach across different biopsy practitioners?Summary Answer: The blastocyst biopsy approach provides highly consistent and reproducible laboratory and clinical outcomes across multiple practitioners from different IVF centres when all of the embryologists received identical training and use similar equipment.What Is Known Already: Recently there has been a trend towards trophectoderm (TE) biopsy in preimplantation genetic screening (PGS)/preimplantation genetic diagnosis (PGD) programmes. However, there is still a lack of knowledge about the reproducibility that can be obtained from multiple biopsy practitioners in different IVF centres in relation also to blastocysts of different morphology. Although it has been demonstrated that biopsy at the blastocyst stage has no impact on embryo viability, it remains a possibility that less experienced individual biopsy practitioners or laboratories performing TE biopsy may affect certain outcomes. We investigated whether TE biopsy practitioners can have an impact on the quality of the genetic test and the subsequent clinical outcomes.Study Design, Size, Duration: This longitudinal cohort study, between April 2013 and December 2014, involved 2586 consecutive blastocyst biopsies performed at three different IVF centres and the analysis of 494 single frozen euploid embryo transfer cycles (FEET).Participants/materials, Setting, Methods: Seven biopsy practitioners performed the blastocyst biopsies in the study period and quantitative PCR was used for comprehensive chromosome screening (CCS). The same practitioner performed both the biopsy and tubing procedures for each blastocyst they biopsied. To investigate the quality of the biopsied samples, the diagnostic rate, sample-specific concurrence and the cell number retrieved in the biopsy were evaluated for each biopsy operator. Clinical outcomes following FEET cycles were stratified by biopsy operator and compared. Cellularity of the biopsy sample was also correlated with clinical outcomes.Main Results and the Role Of Chance: The seven practitioners performed 2586 biopsies, five in centre IVF-1 and one in each of the other two IVF centres (IVF-2 and IVF-3). Overall, 2437 out of 2586 (94.2%) blastocyst biopsies resulted in a conclusive diagnosis, 119 (4.6%) showed a nonconcurrent result and 30 (1.2%) failed to amplify, suggesting the absence of TE cells in the test tube or presence of degenerated/lysed cells only. Among the samples producing a conclusive diagnosis, a mean concurrence value of 0.253 (95% CI = 0.250-0.257) was observed. Logistic regression analysis adjusted for confounding factors showed no differences in the diagnosis rate and in the concurrence of the genetic analysis between different biopsy practitioners. An overall mean number of 7.32 cells (95% CI = 6.82-7.81; range 2-15) were predicted from all biopsies. Higher cellularity was significantly associated with a better quality of the CCS diagnosis (P < 0.01) and with the conclusive diagnosis rate, with nonconcurrent samples showing significantly lower numbers of cells (2.1; 95% CI=1.5-2.7) compared with samples resulting in a conclusive diagnosis (mean cells number 7.5; 95% CI = 7.1-7.9, P < 0.01). However, no differences were recorded between different biopsy practitioners regarding cellularity of the biopsy. Finally, logistic analysis showed no impact of the biopsy practitioners on the observed ongoing rates of implantation, biochemical pregnancy loss and miscarriage after the FEET cycles.Limitations, Reasons For Caution: These data come from a restricted set of laboratories where all of the embryologists received identical training and use identical equipment. A single TE biopsy method and CCS technology was used and these data particularly apply to PGS programmes using blastocyst biopsy without zona opening at the cleavage stage and using qPCR-based CCS. To make firm conclusions on the potential impact of biopsy on biochemical pregnancy loss and miscarriages according to practitioner and biopsy cellularity, a larger sample size is needed.Wider Implications Of the Findings: We reported a very high consistency and reproducibility of the blastocyst biopsy approach coupled with qPCR-based CSS for both genetic and clinical outcomes across different practitioners working in different IVF centres when appropriate training is provided and when the same laboratory setting is used. These data are important considering the trend towards the use of blastocyst biopsy worldwide for PGD/PGS applications.Study Funding/competing Interests: None. [ABSTRACT FROM AUTHOR]

STUDY QUESTION: IS an elective single-embryo transfer (eSET) policy an efficient approach for women aged .35 years when embryo selection is enhanced via blastocyst culture and preimplantation genetic screening (PGS)? SUMMARY ANSWER: Elective SET coupled with enhanced embryo selection using PGS in women older than 35 years reduced the multiple pregnancy rates while maintaining the cumulative success rate of the IVF programme. WHAT IS KNOWN ALREADY: Multiple pregnancies mean an increased risk of premature birth and perinatal death and occur mainly in older patients when multiple embryos are transferred to increase the chance of pregnancy. A SET policy is usually recommended in cases of good prognosis patients, but no general consensus has been reached for SET application in the advanced maternal age (AMA) population, defined as women older than 35 years. Our objective was to evaluate the results in terms of efficacy, efficiency and safety of an eSET policy coupled with increased application of blastocyst culture and PGS for this population of patients in our IVF programme. STUDY DESIGN, SIZE, DURATION: In January 2013, a multidisciplinary intervention involving optimization of embryo selection procedure and introduction of an eSET policy in an AMA population of women was implemented. This is a retrospective 4-year (January 2010-December 2013) pre- and post-intervention analysis, including 1161 and 499 patients in the pre- and post-intervention period, respectively. The primary outcome measures were the cumulative delivery rate (DR) per oocyte retrieval cycle and multiple DR. PARTICIPANTS/MATERIALS, SETTING, METHODS: Surplus oocytes and/or embryos were vitrified during the entire study period. In the post-intervention period, all couples with good quality embryos and less than two previous implantation failures were offered eSET. Embryo selection was enhanced by blastocyst culture and PGS (blastocyst stage biopsy and 24-chromosomal screening). Elective SET was also applied in cryopreservation cycles. MAIN RESULTS AND THE ROLE OF CHANCE: Patient and cycle characteristics were similar in the pre-and post-intervention groups [mean (SD) female age: 39.6 ± 2.1 and 39.4 ± 2.2 years; range 36-44] as assessed by logistic regression. A total of 1609 versus 574 oocyte retrievals, 937 versus 350 embryo warming and 138 versus 27 oocyte warming cycles were performed in the pre- and post-intervention periods, respectively, resulting in 1854 and 508 embryo transfers, respectively. In the post-intervention period, 289 cycles were blastocyst stage with (n = 182) or without PGS (n = 107). A mean (SD) number of 2.9 ±1.1 (range 1-4) and 1.4 ± 0.8 (range 1-3) embryos were transferred pre- and post-intervention, respectively (P, 0.01) and similar cumulative clinical pregnancy rates per transfer and per cycle were obtained: 26.8,30.9% and 29.7,26.3%, respectively. The total DR per oocyte retrieval cycle (21.0 and 20.4% pre- and post-intervention, respectively) defined as efficacy was not affected by the intervention [odds ratio (OR) = 0.8, 95% confidence interval (CI) = 0.7- 1.1; P = 0.23]. However, a significantly increased live birth rate per transferred embryo (defined as efficiency) was observed in the post-intervention group 17.0 versus 10.6% (P < 0.01). Multiple DRs decreased from 21.0 in the preintervention to 6.8% in the post-intervention group (OR = 0.3. 95% CI = 0.1-0.7; P < 0.01). LIMITATIONS, REASONS FOR CAUTION: In this study, the suitability of SET was assessed in individual women on the basis of both clinical and embryological prognostic factors and was not standardized. Forthe described eSET strategy coupled with an enhanced embryo selection policy, an optimized culture system, cryopreservation and aneuploidy screening programme is necessary. WIDER IMPLICATIONS OF THE FINDINGS: Owing to the increased maternal morbidity and perinatal complications related to multiple pregnancies, it is recommended to extend the eSET policy to the AMA population. As shown in this study, enhanced embryo selection procedures might allow a reduction in the number of embryos transferred and the number of transfers to be performed without affecting the total efficacy of the treatment but increasing efficiency and safety. STUDY FUNDING/COMPETING INTEREST(S): None. TRIAL REGISTRATION NUMBER! None. [ABSTRACT FROM AUTHOR]

To evaluate in vitro fertilization (IVF) and perinatal outcomes of donor egg and autologous cycles in patients with advanced reproductive age after undergoing single frozen euploid embryo transfer. A multicenter, retrospective, cohort study. University-affiliated and private IVF centers. Patients aged 39–46 years who underwent IVF with intracytoplasmic sperm injection and preimplantation genetic testing for aneuploidy using whole-chromosome sequencing with donor (n = 278) or autologous (n = 278) oocytes between October 2017 and October 2021. Single frozen euploid embryo transfer with donor or autologous euploid embryo. The main outcome measure was the live birth rate (LBR) after the first embryo transfer, calculated per embryo transfer. The secondary outcomes included the implantation rate, ectopic pregnancy rate, miscarriage rate, and gestational age and birth weight at the time of delivery. Patients using donor or autologous oocytes had a similar likelihood of implantation (57.91% [51.87–63.78] vs. 57.19% [51.15–63.09]) and LBR (41.01% [95% confidence interval {CI}, 35.17–47.04] vs. 42.45% [95% CI, 36.56–48.49]). Furthermore, there were no significant differences in the ectopic pregnancy rate (0.72% [0.09–2.57] vs. 0.36% [0.01–1.99]), miscarriage rate (16.19% [12.06–21.05] vs. 14.39% [95% CI, 10.48–19.08]), gestational age (38.50 [38.08–38.92] vs. 39.16 [38.25–40.07] weeks), or birth weight of infants (2,982.25 [2,606.69–3,357.81] vs. 3,128.24 [2,962.30–3,294.17] kg). The univariate analysis showed no association between advanced maternal age and the LBR (relative risk, 1.03 [95% CI, 0.84–1.25]). Multivariate analysis using putative confounders for embryo competency found no associations with LBR (adjusted relative risk, 1.22 [95% CI, 0.75–1.98]). Patients with euploid blastocysts derived from donor or autologous oocytes did not reveal statistically significant differences in the LBR, implantation rate, ectopic pregnancy rate, miscarriage rate, duration of gestation, or infant birth weight. These findings suggest that age-related reproductive decline and/or poor IVF outcomes associated with women with advanced reproductive age undergoing IVF are heavily driven by embryonic aneuploidy. [ABSTRACT FROM AUTHOR]

STUDY QUESTION What are the clinical pregnancy and live birth rates in women who underwent up to two more euploid blastocyst transfers after three failures in the absence of another known factor that affects implantation? SUMMARY ANSWER The fourth and fifth euploid blastocyst transfers resulted in similar live birth rates of 40% and 53.3%, respectively, culminating in a cumulative live birth rate of 98.1% (95% CI = 96.5–99.6%) after five euploid blastocyst transfers. WHAT IS KNOWN ALREADY The first three euploid blastocysts have similar implantation and live birth rates and provide a cumulative live birth rate of 92.6%. STUDY DESIGN, SIZE, DURATION An international multi-center retrospective study was conducted at 25 individual clinics. The study period spanned between January 2012 and December 2022. A total of 123 987 patients with a total of 64 572 euploid blastocyst transfers were screened for inclusion. PARTICIPANTS/MATERIALS, SETTING, METHODS Patients with a history of any embryo transfer at another clinic, history of any unscreened embryo transfer at participating clinics, parental karyotype abnormalities, the use of donor oocytes or a gestational carrier, untreated intracavitary uterine pathology (e.g. polyp, leiomyoma), congenital uterine anomalies, adenomyosis, communicating hydrosalpinx, endometrial thickness <6 mm prior to initiating of progesterone, use of testicular sperm due to non-obstructive azoospermia in the male partner, transfer of an embryo with a reported intermediate chromosome copy number (i.e. mosaic), preimplantation genetic testing cycles for monogenic disorders, or structural chromosome rearrangements were excluded. Ovarian stimulation protocols and embryology laboratory procedures including trophectoderm biopsy followed the usual practice of each center. The ploidy status of blastocysts was determined with comprehensive chromosome screening. Endometrial preparation protocols followed the usual practice of participating centers and included programmed cycles, natural or modified natural cycles. MAIN RESULTS AND THE ROLE OF CHANCE A total of 105 (0.085% of the total population) patients met the criteria and underwent at least one additional euploid blastocyst transfer after failing to achieve a positive pregnancy test with three consecutive euploid blastocyst transfers. Outcomes of the fourth and fifth euploid blastocyst transfers were similar across participating centers. Overall, the live birth rate was similar with the fourth and fifth euploid blastocysts (40% vs 53.3%, relative risk = 1.33, 95% CI = 0.93–1.9, P value = 0.14). Sensitivity analyses excluding blastocysts biopsied on Day 7 postfertilization, women with a BMI >30 kg/m2, cycles using non-ejaculate or donor sperm, double-embryo transfer cycles, and cycles in which the day of embryo transfer was modified due to endometrial receptivity assay test result yielded similar results. Where data were available, the fourth euploid blastocyst had similar live birth rate with the first one (relative risk = 0.84, 95% CI = 0.58–1.21, P  = 0.29). The cumulative live birth rate after five euploid blastocyst transfers was 98.1% (95% CI = 96.5–99.6%). LIMITATIONS, REASONS FOR CAUTION Retrospective design has its own inherent limitations. Patients continuing with a further euploid embryo transfer and patients dropping out from treatment after three failed euploid transfers can be systematically different, perhaps with regard to ovarian reserve or economic status. WIDER IMPLICATION OF THE FINDINGS Implantation failure seems to be mainly due to embryonic factors. Given the stable and high live birth rates up to five euploid blastocysts, unexplained recurrent implantation failure should have a prevalence of <2%. Proceeding with another embryo transfer can be the best next step once a known etiology for implantation failure is ruled out. STUDY FUNDING/COMPETING INTEREST(s) None. TRIAL REGISTRATION NUMBER N/A. [ABSTRACT FROM AUTHOR]

Objective: To compare the euploid blastocyst formation rates obtained after follicular phase (FP) versus luteal phase (LP) stimulation performed in the same menstrual cycle in a preimplantation genetic diagnosis for aneuploidy testing (PGD-A) program in patients with reduced ovarian reserve.Design: Prospective paired noninferiority observational study.Setting: Private infertility program.Patient(s): Forty-three reduced ovarian reserve patients undergoing a PGD-A.Intervention(s): Both FP and LP stimulations using follicle-stimulating hormone and luteinizing hormone in combination with gonadotropin-releasing hormone (GnRH) antagonist starting on day 2 of the cycle and 5 days after the first oocyte retrieval, respectively, where GnRH agonist was used for both FP and LP ovulation triggering; a trophectoderm biopsy quantitative polymerase chain reaction-based PGD-A strategy; and single euploid blastocyst transfers during a subsequent natural cycle.Main Outcome Measure(s): Primary Outcome Measure: euploid blastocyst rate per injected metaphase 2 (MII) oocyte; secondary outcome measures: number of cumulus-oocyte complexes (COCs), MII oocytes, and blastocysts.Result(s): Patients with an antimüllerian hormone level of <1.5 ng/mL, antral follicle count of <6 follicles, and/or <5 oocytes retrieved in a previous cycle were included. No statistically significant differences were found in the number of retrieved COCs (5.1 ± 3.4 vs. 5.7 ± 3.3), MII oocytes (3.4 ± 1.9 vs. 4.1 ± 2.5), or biopsied blastocysts per stimulated cycle (1.2 ± 1.2 vs. 1.4 ± 1.7) from FP versus LP stimulation, respectively. No differences were observed in the euploid blastocyst rate calculated either per biopsied blastocyst (46.9% vs. 44.8%) or injected MII oocyte (16.2% vs. 15.0%).Conclusion(s): Stimulation with an identical protocol in the FP and LP of the same menstrual cycle resulted in a similar number of blastocysts in patients with reduced ovarian response. The LP stimulation statistically significantly contributed to the final transferable blastocyst yield, thus increasing the number of patients undergoing transfer per menstrual cycle. [ABSTRACT FROM AUTHOR]

Objective: To assess whether extracellular microRNAs (miRNAs) can be accurately profiled from spent blastocyst culture media (SBM) and used as embryonic biomarkers.Design: Prospective cohort study.Setting: Private and academic in vitro fertilization centers.Patient(s): Inner cell mass-free trophectoderm (TE) samples and their relative SBM from five good-quality human blastocysts.Intervention(s): Protocol for miRNA purification and analysis based on quantitative polymerase chain reaction set and validated on human embryonic stem cells (hESCs) and on SBM with and without biological variability.Main Outcomes Measure(s): Analysis of miRNAs in culture media in relation with TE cells and comparison of miRNA profiles between implanted and unimplanted euploid blastocysts.Result(s): Culture media from embryos in the cleavage, morula, and blastocyst stages were collected to investigate the presence of miRNAs. The SBM were prospectively collected from euploid implanted (n = 25) and unimplanted blastocysts (n = 28) for comparison. We hypothesized that human embryos secrete miRNAs in culture media that can be used as biomarkers. The comparative analysis of TE and SBM samples revealed that 96.6% (57 of 59; 95 CI, 88.3-99.6) of the miRNAs detected in the SBM were expressed from TE cells, suggesting a TE origin. The culture media collected from cleavage and morula stage embryos showed a pattern similar to blanks, suggesting that miRNAs profiling from spent culture media applies only for blastocysts. MicroRNAs analysis of SBM from euploid implanted and unimplanted blastocysts highlighted two miRNAs (miR-20a, miR-30c) that showed increased concentrations in the former and were predicted in silico to be involved in 23 implantation-related pathways.Conclusion(s): MicroRNAs secreted from human blastocysts in culture media can be profiled with high reproducibility, and this approach can be further explored for noninvasive embryo selection. [ABSTRACT FROM AUTHOR]

BACKGROUND A normal chromosomal constitution defined through PGT-A assessing all chromosomes on trophectoderm (TE) biopsies represents the strongest predictor of embryo implantation. Yet, its positive predictive value is not higher than 50–60%. This gap of knowledge on the causes of euploid blastocysts' reproductive failure is known as 'the black box of implantation'. OBJECTIVE AND RATIONALE Several embryonic, maternal, paternal, clinical, and IVF laboratory features were scrutinized for their putative association with reproductive success or implantation failure of euploid blastocysts. SEARCH METHODS A systematic bibliographical search was conducted without temporal limits up to August 2021. The keywords were '(blastocyst OR day5 embryo OR day6 embryo OR day7 embryo) AND (euploid OR chromosomally normal OR preimplantation genetic testing) AND (implantation OR implantation failure OR miscarriage OR abortion OR live birth OR biochemical pregnancy OR recurrent implantation failure)'. Overall, 1608 items were identified and screened. We included all prospective or retrospective clinical studies and randomized-controlled-trials (RCTs) that assessed any feature associated with live-birth rates (LBR) and/or miscarriage rates (MR) among non-mosaic euploid blastocyst transfer after TE biopsy and PGT-A. In total, 41 reviews and 372 papers were selected, clustered according to a common focus, and thoroughly reviewed. The PRISMA guideline was followed, the PICO model was adopted, and ROBINS-I and ROB 2.0 scoring were used to assess putative bias. Bias across studies regarding the LBR was also assessed using visual inspection of funnel plots and the trim and fill method. Categorical data were combined with a pooled-OR. The random-effect model was used to conduct the meta-analysis. Between-study heterogeneity was addressed using I 2. Whenever not suitable for the meta-analysis, the included studies were simply described for their results. The study protocol was registered at http://www.crd.york.ac.uk/PROSPERO/ (registration number CRD42021275329). OUTCOMES We included 372 original papers (335 retrospective studies, 30 prospective studies and 7 RCTs) and 41 reviews. However, most of the studies were retrospective, or characterized by small sample sizes, thus prone to bias, which reduces the quality of the evidence to low or very low. Reduced inner cell mass (7 studies, OR: 0.37, 95% CI: 0.27–0.52, I 2 = 53%), or TE quality (9 studies, OR: 0.53, 95% CI: 0.43–0.67, I 2 = 70%), overall blastocyst quality worse than Gardner's BB-grade (8 studies, OR: 0.40, 95% CI: 0.24–0.67, I 2 = 83%), developmental delay (18 studies, OR: 0.56, 95% CI: 0.49–0.63, I 2 = 47%), and (by qualitative analysis) some morphodynamic abnormalities pinpointed through time-lapse microscopy (abnormal cleavage patterns, spontaneous blastocyst collapse, longer time of morula formation I, time of blastulation (tB), and duration of blastulation) were all associated with poorer reproductive outcomes. Slightly lower LBR, even in the context of PGT-A, was reported among women ≥38 years (7 studies, OR: 0.87, 95% CI: 0.75–1.00, I 2 = 31%), while obesity was associated with both lower LBR (2 studies, OR: 0.66, 95% CI: 0.55–0.79, I 2 = 0%) and higher MR (2 studies, OR: 1.8, 95% CI: 1.08–2.99, I 2 = 52%). The experience of previous repeated implantation failures (RIF) was also associated with lower LBR (3 studies, OR: 0.72, 95% CI: 0.55–0.93, I 2 = 0%). By qualitative analysis, among hormonal assessments, only abnormal progesterone levels prior to transfer were associated with LBR and MR after PGT-A. Among the clinical protocols used, vitrified-warmed embryo transfer was more effective than fresh transfer (2 studies, OR: 1.56, 95% CI: 1.05–2.33, I 2 = 23%) after PGT-A. Lastly, multiple vitrification-warming cycles (2 studies, OR: 0.41, 95% CI: 0.22–0.77, I 2 = 50%) or (by qualitative analysis) a high number of cells biopsied may slightly reduce the LBR, while simultaneous zona-pellucida opening and TE biopsy allowed better results than the Day 3 hatching-based protocol (3 studies, OR: 1.41, 95% CI: 1.18–1.69, I 2 = 0%). WIDER IMPLICATIONS Embryo selection aims at shortening the time-to-pregnancy, while minimizing the reproductive risks. Knowing which features are associated with the reproductive competence of euploid blastocysts is therefore critical to define, implement, and validate safer and more efficient clinical workflows. Future research should be directed towards: (i) systematic investigations of the mechanisms involved in reproductive aging beyond de novo chromosomal abnormalities, and how lifestyle and nutrition may accelerate or exacerbate their consequences; (ii) improved evaluation of the uterine and blastocyst-endometrial dialogue, both of which represent black boxes themselves; (iii) standardization/automation of embryo assessment and IVF protocols; (iv) additional invasive or preferably non-invasive tools for embryo selection. Only by filling these gaps we may finally crack the riddle behind 'the black box of implantation'. [ABSTRACT FROM AUTHOR]

This article discusses a randomized controlled trial that compares a conventional stimulation protocol with an unconventional approach involving double oocyte retrieval and continuous FSH administration in IVF. The study found that the unconventional protocol did not increase the number of mature oocytes compared to the conventional protocol. However, the authors caution against generalizing these findings to all double stimulation protocols, as the study had a small sample size and did not include a washout period between stimulations. The authors also raise concerns about the rationale for continuous FSH administration and the choice of transfer strategies. Overall, the study provides guidance on which protocols and patient populations to avoid for a multicycle approach conducted via double stimulation in the same ovarian cycle. [Extracted from the article]

Purpose: To investigate whether high relative humidity conditions (HC), when using a time-lapse system (TLS) with sequential culture media, are beneficial to embryo culture, improving ongoing pregnancy rates. Methods: We included patients undergoing their first ICSI cycle treatment from April 2021 to May 2022. Patients assigned to dry conditions (DC) or HC were 278 and 218, respectively. We used a GERI TLS, three chambers configured in humidity conditions and three in dry conditions. The effect of HC on ongoing pregnancy rate was assessed by the propensity matched sample, to reduce potential differences between women undergoing either HC or DC and reduce biased estimation of treatment effect. Result: After adjusting for several confounding variables and applying the propensity score (PS), no significant differences were observed in the rates of normal (2PN) and abnormal (1PN and 3PN) fertilization, blastulation, top-quality blastocysts, frozen blastocysts, ongoing pregnancies, and miscarriages. The 2-cell (t2) and 4-cell (t4) stages and cell divisions between such stages occurred earlier and were more synchronous in the in DC. Conclusion: These results suggest that HC conditions do not improve the rate of ongoing pregnancy and several embryological outcomes, under the conditions used in this study based on a time-lapse system and sequential culture with day 3 medium change-over. [ABSTRACT FROM AUTHOR]

Purpose: Infertility is increasing worldwide, and many couples seek IVF. Clinical management and laboratory work are fundamental in the IVF journey. Therefore, the definition of reliable key performance indicators (KPIs) based on clinical and laboratory parameters, is essential for internal quality control (IQC). Laboratory performance indicators have been identified and a first attempt to also determine clinical ones has been recently published. However, more detailed indicators are required. Methods: An Italian group of experts in Reproductive Medicine from both public and private clinics on behalf of SIFES-MR and SIERR was established to define IVF indicators to monitor clinical performance. Results: The working group built a consensus on a list of KPIs, performance indicators (PIs) and recommendation indicators (RIs). When deemed necessary, the reference population was stratified by woman age, response to ovarian stimulation and adoption of preimplantation genetic testing for aneuploidies (PGT-A). Each indicator was scored with a value from 1 to 5 and a weighted average formula – considering all the suggested parameters—was defined. This formula generates a center performance score, indicating low, average, good, or excellent performance. Conclusion: This study is intended to provide KPIs, PIs and RIs that encompass several essential aspects of a modern IVF clinic, including quality control and constant monitoring of clinical and embryological features. These indicators could be used to assess the quality of each center with the aim of improving efficacy and efficiency in IVF. [ABSTRACT FROM AUTHOR]

Human embryos are very frequently affected by maternally inherited aneuploidies, which in the vast majority of cases determine developmental failure at pre- or post-implantation stages. However, recent evidence, generated by the alliance between diverse technologies now routinely employed in the IVF laboratory, has revealed a broader, more complex scenario. Aberrant patterns occurring at the cellular or molecular level can impact at multiple stages of the trajectory of development to blastocyst. In this context, fertilization is an extremely delicate phase, as it marks the transition between gametic and embryonic life. Centrosomes, essential for mitosis, are assembled ex novo from components of both parents. Very large and initially distant nuclei (the pronuclei) are brought together and positioned centrally. The overall cell arrangement is converted from being asymmetric to symmetric. The maternal and paternal chromosome sets, initially separate and scattered within their respective pronuclei, become clustered where the pronuclei juxtapose, to facilitate their assembly in the mitotic spindle. The meiotic spindle is replaced by a segregation machinery that may form as a transient or persistent dual mitotic spindle. Maternal proteins assist the decay of maternal mRNAs to allow the translation of newly synthesized zygotic transcripts. The diversity and complexity of these events, regulated in a precise temporal order and occurring in narrow time windows, make fertilization a highly error-prone process. As a consequence, at the first mitotic division, cellular or genomic integrity may be lost, with fatal consequences for embryonic development. [ABSTRACT FROM AUTHOR]

Chromosome deletions and duplications-copy number variations (CNVs)-are a major contribution to the genome variability and can be either pathogenic or not. A particular class, the microdeletions and microduplications, which alter <5 Mb, have been extensively associated with developmental delay and intellectual disability. Although their prevalence in pregnancies and newborn is relatively low, their estimates in preimplantation embryos are poorly defined. The introduction of novel technologies for preimplantation genetic diagnosis of aneuploidies (PGD-A) caused new possibilities and challenges associated with diagnosis of subchromosomal CNVs. Both technical aspects of performing genomewide microarray or next generation sequencing analysis on single cells and interpretation issues are subject of debate. The latter include the reliability of detection of CNVs from embryonic biopsies, their clinical classification based on reproductive outcomes, as well as how before and after test counseling should be organized. It is also important to consider that the current resolution of these technologies from single cells is usually >10 Mb, thus ruling out the possibility to diagnose the most important recurrent microdeletion and microduplication syndromes. Furthermore, at present we face with a lack of well-designed studies addressing the actual resolution and accuracy of CNVs detection in PGD-A and no reference databases is available to evaluate their pathogenicity. Accordingly, it seems reasonable at the moment to avoid the reporting of subchromosomal CNVs in PGD-A. However, although these issues require proper handling, they should not lead us away from providing an improved preimplantation genetic diagnosis. [ABSTRACT FROM AUTHOR]

Preimplantation genetic testing for aneuploidies (PGT-A) is arguably the most effective embryo selection strategy. Nevertheless, it requires greater workload, costs, and expertise. Therefore, a quest towards user-friendly, non-invasive strategies is ongoing. Although insufficient to replace PGT-A, embryo morphological evaluation is significantly associated with embryonic competence, but scarcely reproducible. Recently, artificial intelligence-powered analyses have been proposed to objectify and automate image evaluations. iDAScore v1.0 is a deep-learning model based on a 3D convolutional neural network trained on time-lapse videos from implanted and non-implanted blastocysts. It is a decision support system for ranking blastocysts without manual input. This retrospective, pre-clinical, external validation included 3604 blastocysts and 808 euploid transfers from 1232 cycles. All blastocysts were retrospectively assessed through the iDAScore v1.0; therefore, it did not influence embryologists' decision-making process. iDAScore v1.0 was significantly associated with embryo morphology and competence, although AUCs for euploidy and live-birth prediction were 0.60 and 0.66, respectively, which is rather comparable to embryologists' performance. Nevertheless, iDAScore v1.0 is objective and reproducible, while embryologists' evaluations are not. In a retrospective simulation, iDAScore v1.0 would have ranked euploid blastocysts as top quality in 63% of cases with one or more euploid and aneuploid blastocysts, and it would have questioned embryologists' ranking in 48% of cases with two or more euploid blastocysts and one or more live birth. Therefore, iDAScore v1.0 may objectify embryologists' evaluations, but randomized controlled trials are required to assess its clinical value. [ABSTRACT FROM AUTHOR]

A study published in the journal Human Reproduction analyzed the outcomes of 123,987 patients from 26 clinics in three continents to investigate the prevalence of recurrent implantation failure (RIF). The study found that RIF is much less common than previously believed. The study included patients who had undergone up to five euploid blastocyst transfers, ruling out known causes of implantation failure. The results were consistent across multiple sensitivity analyses and were unaffected by factors such as the number of eggs retrieved, BMI, or the use of preimplantation genetic testing for aneuploidy (PGT-A) or endometrial receptivity array (ERA). The study does not recommend or discourage the use of PGT-A or ERA, but rather provides evidence against the presence of an obscure endometrial/uterine/maternal factor in cases of implantation failure. The authors of the study have no conflicts of interest to declare. [Extracted from the article]

Purpose: An impact of different gonadotrophins selection for ovarian stimulation (OS) on oocyte competence has yet to be defined. In this study, we asked whether an association exists between OS protocol and euploid blastocyst rate (EBR) per metaphase-II (MII) oocytes. Methods: Cycles of first preimplantation genetic testing for aneuploidies conducted by women ≥ 35 years old with their own metaphase-II oocytes inseminated in the absence of severe male factor (years 2014–2018) were clustered based on whether recombinant FSH (rec-FSH) or human menopausal gonadotrophin (HMG) was used for OS, then matched for the number of fresh inseminated eggs. Four groups were outlined: rec-FSH (N = 57), rec-FSH plus rec-LH (N = 55), rec-FSH plus HMG (N = 112), and HMG-only (N = 127). Intracytoplasmic sperm injection, continuous blastocyst culture, comprehensive chromosome testing to assess full-chromosome non-mosaic aneuploidies and vitrified-warmed euploid single embryo transfers (SETs) were performed. The primary outcome was the EBR per cohort of MII oocytes. The secondary outcome was the live birth rate (LBR) per first SETs. Results: Rec-FSH protocol was shorter and characterized by lower total gonadotrophin (Gn) dose. The linear regression model adjusted for maternal age showed no association between the Gn adopted for OS and EBR per cohort of MII oocytes. Similarly, no association was reported with the LBR per first SETs, even when adjusting for blastocyst quality and day of full blastulation. Conclusion: In view of enhanced personalization in OS, clinicians shall focus on different endpoints or quantitative effects related to Gn action towards follicle recruitment, development, and atresia. Here, LH and/or hCG was administered exclusively to women with expected sub/poor response; therefore, we cannot exclude that specific Gn formulations may impact patient prognosis in other populations. [ABSTRACT FROM AUTHOR]

BACKGROUND Folliculogenesis occurs in the highly dynamic environment of the ovary. Follicle cyclic recruitment, neo-angiogenesis, spatial displacement, follicle atresia and ovulation stand out as major events resulting from the interplay between mechanical forces and molecular signals. Morphological and functional changes to the growing follicle and to the surrounding tissue are required to produce oocytes capable of supporting preimplantation development to the blastocyst stage. OBJECTIVE AND RATIONALE This review will summarize the ovarian morphological and functional context that contributes to follicle recruitment, growth and ovulation, as well as to the acquisition of oocyte developmental competence. We will describe the changes occurring during folliculogenesis to the ovarian extracellular matrix (ECM) and to the vasculature, their influence on the mechanical properties of the ovarian tissue, and, in turn, their influence on the regulation of signal transduction. Also, we will outline how their dysregulation might be associated with pathologies such as polycystic ovary syndrome (PCOS), endometriosis or premature ovarian insufficiency (POI). Finally, for each of these three pathologies, we will highlight therapeutic strategies attempting to correct the altered biomechanical context in order to restore fertility. SEARCH METHODS For each area discussed, a systematic bibliographical search was performed, without temporal limits, using PubMed Central, Web of Science and Scopus search engines employing the keywords extracellular matrix, mechanobiology, biomechanics, vasculature, angiogenesis or signalling pathway in combination with: ovary, oogenesis, oocyte, folliculogenesis, ovarian follicle, theca, granulosa, cumulus, follicular fluid, corpus luteum, meiosis, oocyte developmental competence, preimplantation, polycystic ovary syndrome, premature ovarian insufficiency or endometriosis. OUTCOMES Through search engines queries, we yielded a total of 37 368 papers that were further selected based on our focus on mammals and, specifically, on rodents, bovine, equine, ovine, primates and human, and also were trimmed around each specific topic of the review. After the elimination of duplicates, this selection process resulted in 628 papers, of which 287 were cited in the manuscript. Among these, 89.2% were published in the past 22 years, while the remaining 8.0%, 2.4% or 0.3% were published during the 1990s, 1980s or before, respectively. During folliculogenesis, changes occur to the ovarian ECM composition and organization that, together with vasculature modelling around the growing follicle, are aimed to sustain its recruitment and growth, and the maturation of the enclosed oocyte. These events define the scenario in which mechanical forces are key to the regulation of cascades of molecular signals. Alterations to this context determine impaired folliculogenesis and decreased oocyte developmental potential, as observed in pathological conditions which are causes of infertility, such as PCOS, endometriosis or POI. WIDER IMPLICATIONS The knowledge of these mechanisms and the rules that govern them lay a sound basis to explain how follicles recruitment and growth are modulated, and stimulate insights to develop, in clinical practice, strategies to improve follicular recruitment and oocyte competence, particularly for pathologies like PCOS, endometriosis and POI. [ABSTRACT FROM AUTHOR]

The gut microbiota (GM) is a complex and dynamic population of microorganisms living in the human gastrointestinal tract that play an important role in human health and diseases. Recent evidence suggests a strong direct or indirect correlation between GM and both male and female fertility: on the one hand, GM is involved in the regulation of sex hormone levels and in the preservation of the blood–testis barrier integrity; on the other hand, a dysbiotic GM is linked to the onset of pro-inflammatory conditions such as endometriosis or PCOS, which are often associated with infertility. Exposure to endocrine-disrupting chemicals (EDCs) is one of the main causes of GM dysbiosis, with important consequences to the host health and potential transgenerational effects. This perspective article aims to show that the negative effects of EDCs on reproduction are in part due to a dysbiotic GM. We will highlight (i) the link between GM and male and female fertility; (ii) the mechanisms of interaction between EDCs and GM; and (iii) the importance of the maternal–fetal GM axis for offspring growth and development. [ABSTRACT FROM AUTHOR]

Preimplantation Genetic Diagnosis and Screening (PGD/PGS) for monogenic diseases and/or numerical/structural chromosomal abnormalities is a tool for embryo testing aimed at identifying nonaffected and/or euploid embryos in a cohort produced during an IVF cycle. A critical aspect of this technology is the potential detrimental effect that the biopsy itself can have upon the embryo. Different embryo biopsy strategies have been proposed. Cleavage stage blastomere biopsy still represents the most commonly used method in Europe nowadays, although this approach has been shown to have a negative impact on embryo viability and implantation potential. Polar body biopsy has been proposed as an alternative to embryo biopsy especially for aneuploidy testing. However, to date no sufficiently powered study has clarified the impact of this procedure on embryo reproductive competence. Blastocyst stage biopsy represents nowadays the safest approach not to impact embryo implantation potential. For this reason, as well as for the evidences of a higher consistency of the molecular analysis when performed on trophectoderm cells, blastocyst biopsy implementation is gradually increasing worldwide. The aim of this review is to present the evidences published to date on the impact of the biopsy at different stages of preimplantation development upon human embryos reproductive potential. [ABSTRACT FROM AUTHOR]

Purpose: The risk of monozygotic twins (MZTs) is increased in couples undergoing assisted reproductive technology (ART) treatments. Several systematic reviews have investigated the possible determinants linked to ART, but results obtained have not been conclusive. The study aims to investigate whether the incidence of MZT differed among ART centers. Methods: This is a multicenter retrospective cohort study using the Italian ART National Registry database and involving the centers reporting data from individual ART cycles from 2015 to 2019. To investigate the incidence of MZT, only single embryo transfer cycles were considered. Women who had sex-discordant deliveries were excluded. MZT rate was calculated as the number of multiple pregnancies (more than one gestational sac at first ultrasound) out of the total number of clinical pregnancies. A binomial distribution model was used to determine the 95% CI of the frequency of MZT. Results: Eighteen centers were included, and they provided data on 10,433 pregnancies. The total number of MZT was 162, corresponding to an incidence of 1.5% (95% CI: 1.3–1.8%). The rate of MZT among centers varied between 0% (95% CI: 0.0–25.9%) and 3.2% (95% CI: 1.3–8.1%). All the 95% CIs included 1.5%, rejecting the hypothesis that the MZT rate may significantly differ among centers. Conclusions: The rate of MZT did not significantly vary among ART centers. Local factors are unlikely to explain the increased rate of MZT in ART pregnancies. [ABSTRACT FROM AUTHOR]

Purpose: Since the end of February 2020, SARS-CoV-2 dramatically spread in Italy. To ensure that most of National Health System (NHS) resources were employed to control the pandemic, non-urgent medical procedures (including IVF) were suspended in March 2020. Here, we aimed at assessing the impact of the restrictive measures on Italian IVF activity. Methods: In May 2020, the Italian ART Register launched an online survey (multiple choices and open answers) across ART centers (89.0% response rate; N = 170/191) to investigate how they were facing the emergency and estimate the reduction in their activity. In February 2022, the official data of the whole 2020 were published and retrospectively analyzed. The ART cycles conducted in Italy in 2020 (67,928 by 57,423 patients) were then compared to those conducted in 2019 (82,476 by 67,633 patients). The estimates formulated through the survey were compared to the actual reduction. Results: In 2020, 14,548 less IVF cycles were conducted with respect to 2019 (− 17.6% reduction). This led to 2539 fewer live births (− 19.8%) than 2019. If the reduction unveiled by the survey launched in May 2020 (i.e., − 35%) would have persisted throughout 2020, a significantly larger impact was expected (4200 less newborns). Instead, the activity was gradually recovered, and it compensated the months of greatest emergency, thus fulfilling the most optimistic scenario. Conclusions: Italy suffers from the lowest birth rate in Europe, and COVID-19 impact on IVF-derived live births testified how key ART is for Italian demographics. The government should support access to these treatments with dedicated actions. [ABSTRACT FROM AUTHOR]

Environmental toxicants (ETs) are an exogenous chemical group diffused in the environment that contaminate food, water, air and soil, and through the food chain, they bioaccumulate into the organisms. In mammals, the exposure to ETs can affect both male and female fertility and their reproductive health through complex alterations that impact both gametogeneses, among other processes. In humans, direct exposure to ETs concurs to the declining of fertility, and its transmission across generations has been recently proposed. However, multi- and transgenerational inheritances of ET reprotoxicity have only been demonstrated in animals. Here, we review recent studies performed on laboratory model animals investigating the effects of ETs, such as BPA, phthalates, pesticides and persistent contaminants, on the reproductive system transmitted through generations. This includes multigenerational effects, where exposure to the compounds cannot be excluded, and transgenerational effects in unexposed animals. Additionally, we report on epigenetic mechanisms, such as DNA methylation, histone tails and noncoding RNAs, which may play a mechanistic role in a nongenetic transmission of environmental information exposure through the germline across generations. [ABSTRACT FROM AUTHOR]

Vitrification is now the dominant approach for cryopreservation of human oocytes and embryos; however, serious disagreement persists, particularly about biosafety issues. Techniques are categorized as either ‘open’ or ‘closed’ according to occurrence of direct contact between the medium and liquid nitrogen during cryopreservation. Advocates of closed systems emphasize the potential danger of disease transmission mediated through liquid nitrogen, and praise the safety of their approach; those who use the open systems refer to the lack of evidence of disease transmission and regard their systems as more consistent and efficient. The purpose of this review is to clarify whether open and closed systems are really open and closed; if closed systems are safe and free of any danger of contamination; if closed systems are equally efficient as open ones for cryopreservation of human embryos and oocytes by considering overall outcome; and finally, if ethical and legal concerns are sound when risks and benefits are considered in a broader sense. On the basis of these answers, implementation of rational measures to lower the theoretical danger of disease transmission are proposed while maintaining the achievements in cryopreservation that have contributed substantially to the advancement in assisted reproduction techniques during the past decade. [ABSTRACT FROM AUTHOR]

Study Question: What is the clinical value of Day 7 blastocysts?Summary Answer: Ending embryo culture at 144 hours post-insemination (h.p.i.; i.e. 6 days) would involve 7.3% and 4.4% relative reductions in the number of patients obtaining euploid blastocysts and live birth(s) (LBs), respectively.What Is Known Already: Many studies showed that Day 7 blastocysts are clinically valuable, although less euploid and less competent than faster-growing embryos. Nevertheless, a large variability exists in: (i) the definition of 'Day 7'; (ii) the criteria to culture embryos to Day 7; (iii) the clinical setting; (iv) the local regulation; and/or (v) the culture strategies and incubators. Here, we aimed to iron out these differences and portray Day 7 blastocysts with the lowest possible risk of bias. To this end, we have also adopted an artificial intelligence (AI)-powered software to automatize developmental timings annotations and standardize embryo morphological assessment.Study Design, Size and Duration: Observational study including 1966 blastocysts obtained from 681 patients cultured in a time-lapse incubator between January 2013 and December 2020 at a private Italian IVF center.Participants/materials, Setting, Methods: According to Italian Law 40/2004, embryos were not selected based on their morphology and culture to ≥168 h.p.i. is standard care at our center. ICSI, continuous culture with Day 5 media refresh, trophectoderm biopsy without assisted hatching and comprehensive chromosome testing (CCT) to diagnose full-chromosome non-mosaic aneuploidies, were all performed. Blastocysts were clustered in six groups based on the time of biopsy in h.p.i. at 12 hr intervals starting from <120 h.p.i. (set as control) up to >168 h.p.i. Blastocyst quality was assessed using Gardner's scheme and confirmed with AI-powered software. AI was also used to automatically annotate the time of expanding blastocyst (tEB) and the hours elapsing between this moment and the achievement of full expansion when blastocysts were biopsied and vitrified. Also, blastocyst area at tEB and at the time of biopsy was automatically assessed, as well as the hour of the working day when the procedure was performed. The main outcomes were the euploidy rate and the LB rate (LBR) per vitrified-warmed euploid single blastocyst transfer. The results were adjusted for confounders through multivariate logistic regressions. To increase their generalizability, the main outcomes were reported also based on a 144-h.p.i. cutoff (i.e. 6 exact days from ICSI). Based on this cutoff, all the main patient outcomes (i.e. number of patients obtaining blastocysts, euploid blastocysts, LBs, with supernumerary blastocysts without a LB and with surplus blastocysts after an LB) were also reported versus the standard care (>168 h.p.i.). All hypothetical relative reductions were calculated.Main Results and the Role Of Chance: A total of 14.6% of the blastocysts reached full expansion beyond 144 h.p.i. (5.9% in the range 144-156 h.p.i., 7.9% in the range 156-168 h.p.i. and 0.8% beyond 168 h.p.i.). Slower blastocysts were of a worse quality based on the evaluation of both embryologists and AI. Both later tEB and longer time between tEB and full blastocyst expansion concurred to Day 7 development, quite independently of blastocyst quality. Slower growing blastocysts were slightly larger than faster-growing ones at the time of biopsy, but no difference was reported in the risk of hatching, mainly because two dedicated slots have been set along the working day for these procedures. The lower euploidy rate among Day 7 blastocysts is due to their worse morphology and more advanced oocyte age, rather than to a slower development per se. Conversely, the lower LBR was significant even after adjusting for confounders, with a first relevant decrease for blastocysts biopsied in the range 132-144 h.p.i. (N = 76/208, 36.5% versus N = 114/215, 53.0% in the control, multivariate odds ratio 0.61, 95% CI 0.40-0.92, adjusted-P = 0.02), and a second step for blastocysts biopsied in the range 156-168 h.p.i. (N = 3/21, 14.3%, multivariate odds ratio: 0.24, 95% CI 0.07-0.88, adjusted-P = 0.03). Nevertheless, when the cutoff was set at 144 h.p.i., no significant difference was reported. In this patient population, ending embryo culture at 144 h.p.i. would have caused 10.6%, 7.3%, 4.4%, 13.7% and 5.2% relative reductions in the number of patients obtaining blastocysts, euploid blastocysts, LBs, supernumerary blastocysts without an LB and surplus blastocysts after an LB, respectively.Limitations, Reasons For Caution: Gestational and perinatal outcomes were not assessed, and a cost-effectiveness analysis is missing. Moreover, we encourage other groups to investigate this topic with different culture and biopsy protocols, as well as in different clinical settings and regulatory contexts.Wider Implications Of the Findings: In view of the increasing personalization and patient-centeredness of IVF, whenever allowed from the local regulations, the choice to culture embryos to Day 7 should be grounded on the careful evaluation of couples' reproductive history. Patients should be aware that Day 7 blastocysts are less competent than faster-growing ones; still, poor prognosis couples, couples less compliant toward other attempts in case of a failure and couples wishing for more than one child, may benefit from them. AI tools can help improving the generalizability of the evidence worldwide.Study Funding/competing Interest(s): This study did not receive any funding. I.E., A.B.M. and I.H.-V. are employees of Fairtility Ltd.Trial Registration Number: N/A. [ABSTRACT FROM AUTHOR]

In recent years a troubling trend has emerged in the medical research field, notably in reproductive medicine, manifesting an increased emphasis on quantity over quality in articles published. The pressure to collect copious publication records risks compromising meticulous expertise and impactful contributions. This tendency is exemplified by the rise of 'hyper-prolific researchers' publishing at an extraordinary rate (i.e. every 5 days), prompting a deeper analysis of the reasons underlying this behaviour. Prioritizing rapid publication over Galileo Galilei's systematic scientific principles may lead to a superficial approach driven by quantitative targets. Thus, the overreliance on metrics to facilitate academic careers has shifted the focus to numerical quantification rather than the real scientific contribution, raising concerns about the effectiveness of the evaluation systems. The Hamletian question is: are we scientist or journalist? Addressing these issues could necessitate a crucial re-evaluation of the assessment criteria, emphasizing a balance between quantity and quality to foster an academic environment that values meaningful contributions and innovation. [ABSTRACT FROM AUTHOR]

Oocyte developmental competence is defined as the capacity of the female gamete to be fertilized and sustain development to the blastocyst stage. Epigenetic reprogramming, a correct cell division pattern, and an efficient DNA damage response are all critical events that, before embryonic genome activation, are governed by maternally inherited factors such as maternal-effect gene (MEG) products. Although these molecules are stored inside the oocyte until ovulation and exert their main role during fertilization and preimplantation development, some of them are already functioning during folliculogenesis and oocyte meiosis resumption. This mini review summarizes the crucial roles played by MEGs during oocyte maturation, fertilization, and preimplantation development with a direct/indirect effect on the acquisition or maintenance of oocyte competence. Our aim is to inspire future research on a topic with potential clinical perspectives for the prediction and treatment of female infertility. [ABSTRACT FROM AUTHOR]

Purpose: Our primary objective was to assess whether immediately undergoing a second stimulation in the same ovarian cycle (DuoStim) for advanced-maternal-age and/or poor-ovarian-reserve (AMA/POR) patients obtaining ≤ 3 blastocysts for preimplantation-genetic-testing-for-aneuploidies (PGT-A) is more efficient than the conventional-approach. Methods: All AMA/POR patients obtaining ≤ 3 blastocysts after conventional-stimulation between 2017 and 2019 were proposed DuoStim, and 143 couples accepted (DuoStim-group) and were matched for the main confounders to 143 couples who did not accept (conventional-group). GnRH-antagonist protocol with recombinant-gonadotrophins and agonist trigger, intra-cytoplasmatic-sperm-injection (ICSI) with ejaculated sperm, PGT-A and vitrified-warmed euploid single-blastocyst-transfer(s) were performed. The primary outcome was the cumulative-live-birth-delivery-rate per intention-to-treat (CLBdR per ITT) within 1 year. If not delivering, the conventional-group had 1 year to undergo another conventional-stimulation. A cost-effectiveness analysis was also conducted. Results: The CLBdR was 10.5% in the conventional-group after the first attempt. Only 12 of the 128 non-pregnant patients returned (165 ± 95 days later; drop-out = 116/128,90.6%), and 3 delivered. Thus, the 1-year CLBdR was 12.6% (N = 18/143). In the DuoStim-group, the CLBdR was 24.5% (N = 35/143; p = 0.01), 2 women delivered twice and 13 patients have other euploid blastocysts after a LB (0 and 2 in the conventional-group). DuoStim resulted in an incremental-cost-effectiveness-ratio of 23,303€. DuoStim was costlier and more effective in 98.7% of the 1000 pseudo-replicates generated through bootstrapping, and the cost-effectiveness acceptability curves unveiled that DuoStim would be more cost-effective than the conventional-approach at a willingness-to-pay threshold of 23,100€. Conclusions: During PGT-A treatments in AMA/POR women, DuoStim can be suggested in progress to rescue poor blastocyst yields after conventional-stimulation. It might indeed prevent drop-out or further aging between attempts. [ABSTRACT FROM AUTHOR]

The study aimed to retrospectively evaluate the impact of cryo-storage duration on clinical, obstetric and perinatal outcomes after vitrified-warmed euploid blastocyst transfer. This was an observational study including 2688 vitrified-warmed euploid single blastocyst transfers that was conducted at a private IVF centre between May 2013 and March 2020. It included a total of 1884 women (age 38 ± 3 years) undergoing at least one transfer after preimplantation genetic testing for aneuploidies. The euploid blastocysts transferred were clustered into seven groups according to the cryo-storage duration between vitrification and warming: ≤60 days (n = 646; control group), 61–90 days (n = 599), 91–180 days (n = 679), 181–360 days (n = 405), 361–720 days (n = 144), 721–1080 days (n = 118) and >1080 days (n = 97). The primary outcome was the live birth rate (LBR) per transfer. The secondary outcomes were miscarriage rate, obstetric and perinatal issues. The data were adjusted for confounders through logistic or linear regressions. A significantly lower LBR was reported for transfers performed within 91–180 days (n = 291/679, 42.9%; P = 0.017), 181–360 days (n = 169/405, 41.7%; P = 0.016) and 361–720 days (n = 57/144, 39.6%; P = 0.034) versus ≤60 days (n = 319/646, 49.4%). However, this was mainly due to top-quality embryos being transferred first when more euploid blastocysts were available, thereby leaving lower quality ones for subsequent procedures. Indeed, the multivariate odds ratios adjusted for confounders showed similar results across all cryo-storage duration clusters. No difference was reported also for all secondary outcomes. Cryo-storage duration even beyond 3 years from blastocyst vitrification does not affect clinical, obstetric and perinatal outcomes. [ABSTRACT FROM AUTHOR]

The diagnosis of adenomyosis is feasible on pathological specimen examination, while it is unreliable on clinical findings. biopsy, hysteroscopy, sonohysterography, and routine ultrasound or magnetic resonance imaging. Several patterns of 'abnormality' described on imaging have been linked to adenomyosis, but the correlation is weak and the diagnostic accuracy is low outside of a research context. Nevertheless, thickening or abnormality of the subendometrial myometrium, the outer part of the 'endometrial--subendometrial myometrium unit' (thought to be important in human fertility) has bees repeatedly documented on imaging, called 'adenomyosis' and linked to infertility. This paper discusses the value of the physiological endometrial-- subendometrial myometrium unit in human fertility, reviews the current criteria for its imaging, and reports on its relationship to fertility. It is proposed that endometrial--subendometrial myometrium unit disruption disease is considered as a new entity (distinguished from adenomyosis), the diagnosis of which is feasible and straightforward on imaging and expressed mainly by pathological thickening or abnormality of the subendometrial myometrium (myometrial halo or junctional zone). The study also reports on the influence of abnormal thickening or disruption on human fertility and outcome of assisted reproduction techniques, and demonstrates that this new entity is epidemiologically different from adenomyosis. [ABSTRACT FROM AUTHOR]

The goal of an IVF cycle is the birth of at least one baby per intention to treat. However, IVF cannot confer competence on an embryo, but only can provide each couple with a safe treatment to meet a predetermined chance of success. This commentary highlights how clinical, financial and patient-centred perspectives should be included in the definition of success in IVF. The primary outcome, which is the cumulative live birth delivery rate per intention to treat, must always be complemented by analyses of risks, costs and time invested, as well as by measures of patient satisfaction. Finally, it is essential, whenever clinical conditions exist, to limit treatment discontinuation after failed attempts. Constant monitoring of the data is pivotal and must be adjusted for patient characteristics and compared with national and international registers. The authors aimed to review all these aspects and highlight the points that are still open for discussion. Is it time for a consensus? [ABSTRACT FROM AUTHOR]

Does maternal preconceptional body mass index (BMI) associate with mean blastocyst euploidy rate (m-ER) per patient and live birth rate (LBR) after vitrified–warmed euploid single embryo transfer (SET)? Observational study conducted between April 2013 and March 2020 at a private IVF clinic, involving 1811 Caucasian women undergoing trophectoderm biopsy and comprehensive chromosome testing. The outcomes of 1125 first vitrified–warmed euploid SET were also analysed. Patients were clustered as normal weight (BMI 18.5–25; n = 1392 performing 859 SET), underweight (BMI <18.5; n = 160 performing 112 SET) and overweight (BMI >25; n = 259 performing 154 SET). m-ER per patient was the primary outcome. The secondary outcomes were all clinical outcomes per euploid SET. All data were adjusted for confounders through regression analyses. The m-ER per patient decreases as maternal BMI increases from 17 up to 22–23 before reaching a plateau. A linear regression adjusted for maternal age confirmed this moderate association (unstandardized coefficient B: –0.6%, 95% confidence interval [CI]: –1.1 to –0.1%, P = 0.02). All clinical outcomes were similar between normal weight and underweight women. Overweight women, instead, showed higher miscarriage rate per clinical pregnancy (n = 20/75, 26.7% versus n = 67/461, 14.5%; odds ratio [OR] adjusted for blastocyst quality and day of full blastulation: 2.0, 95% CI: 1.1–3.6, P = 0.01) and lower LBR per SET (n = 55/154, 35.7% versus n = 388/859, 45.2%; OR adjusted for blastocyst quality and day of full blastulation: 0.67, 95% CI: 0.46–0.96, P = 0.03). These data indicate a need for future research on more sensitive metrics to assess body fat mass and distribution, as well as on the mechanisms leading to lipotoxicity, thereby impairing embryo competence and/or endometrial receptivity. Overweight women should be informed of their higher risk for miscarriage and, whenever possible, encouraged to lose weight, especially before transfer. [ABSTRACT FROM AUTHOR]

Objective: To appraise the fertilization rate as a predictive factor for cumulative live birth rate (CLBR).Design: Multicenter retrospective cohort study.Setting: Ten in vitro fertilization clinics, whose data were collected and processed by the assisted reproductive technology (ART) Italian National Registry.Patient(s): 7,968 couples undergoing 9,394 complete intracytoplasmic sperm injection cycles.Intervention(s): None.Main Outcome Measure(s): The primary outcome measure was the CLBR in association with the fertilization rate intervals (<65%-group 1; 65%-80%-group 2; and >80%-group 3). Further data stratification was performed on the basis of maternal age (<34, 35-38, and 39-42 years) and number of retrieved oocytes (5-7, 8-10, and > 10 oocytes).Result(s): The CLBR was progressively higher in relation to the fertilization rate in groups 1, 2, and 3 (20.1%, 34.7%, and 41.3%, respectively). The number of recovered oocytes, embryo number per cycle, and cumulative pregnancy rate followed the same trend. The decrease in CLBR with increasing maternal age was significantly correlated with the fertilization rate and CLBR in all 3 maternal age groups. Multivariate logistic regression analysis showed fertilization rate as a factor independently associated with CLBR.Conclusion(s): The present data indicated a positive association between the fertilization rate and the CLBR, suggesting the predictive clinical relevance of this parameter and its adoption as a key performance indicator. [ABSTRACT FROM AUTHOR]

To compare pregnancy rate and implantation rate in poor responder women, aged over 40 years, who underwent natural cycle versus conventional ovarian stimulation. This is a retrospective single-center cohort study conducted at the GENERA IVF program, Rome, Italy, between September 2012 and December 2018, including only poor responder patients, according to Bologna criteria, of advanced age, who underwent IVF treatment through Natural Cycle or conventional ovarian stimulation. Between September 2012 and December 2018, 585 patients were included within the study. Two hundred thirty patients underwent natural cycle and 355 underwent conventional ovarian stimulation. In natural cycle group, both pregnancy rate per cycle (6.25 vs 12.89%, respectively, p = 0.0001) and pregnancy rate per patient101 with at least one embryo-transfer (18.85 vs 28.11% respectively, p = 0.025) resulted significant reduced. Pregnancy rate per patient managed with conventional ovarian stimulation resulted not significantly different compared with natural cycle (19.72 vs 15.65% respectively, p = 0.228), but embryo implantation rate was significantly higher in patients who underwent natural cycle rather than patient subjected to conventional ovarian stimulation (13 vs 8.28% respectively, p = 0.0468). No significant difference could be detected among the two groups in terms of abortion rate (p = 0.2915) or live birth pregnancy (p = 0.2281). Natural cycle seems to be a valid treatment in patients over 40 years and with a low ovarian reserve, as an alternative to conventional ovarian stimulation. [ABSTRACT FROM AUTHOR]

The aim of this article is to gather 9 thought leaders and their team members to present their ideas about the future of in vitro fertilization and the andrology laboratory. Although we have seen much progress and innovation in the laboratory over the years, there is still much to come, and this article looks at what these leaders think will be important in the future development of technology and processes in the laboratory. [ABSTRACT FROM AUTHOR]

Introduction: Several studies suggest that luteinizing hormone (LH) could improve IVF outcome in women of advanced reproductive age by optimizing androgen production. In this review, we assessed the role of recombinant-human LH (r-hLH) and recombinant human follicle stimulating hormone (r-hFSH) co-treatment in ovarian stimulation for assisted reproductive technology in women of advanced reproductive age candidates for assisted reproduction. Material and methods: Using a preregistered protocol we systematically searched Medline/PubMed, Scopus and the ISI Web of Science databases to identify randomized controlled trials in which r-hFSH monotherapy protocols were compared with r-hFSH/r-hLH co-treatment in women ≥35 years undergoing fresh IVF cycles. We calculated the pooled odds ratio (OR) for dichotomous data and the weight mean difference (WMD) for continuous data with an associated 95% confidence interval (CI). The meta-analyses were conducted using the random-effect model. P values < 0.05 were considered statistically significant. Subgroup analyses of all primary and secondary outcomes were performed only in women aged 35–40 years. Results: Twelve studies were identified. In women aged between 35 and 40 years, r-hFSH/r-hLH co-treatment was associated with higher clinical pregnancy rates (OR 1.45, CI 95% 1.05–2.00, I2 = 0%, P = 0.03) and implantation rates (OR 1.49, CI 95% 1.10–2.01, I2 = 13%, P = 0.01) versus r-hFSH monotherapy. Fewer oocytes were retrieved in r-hFSH/r-hLH-treated patients than in r-hFSH-treated patients both in women aged ≥35 years (WMD -0.82 CI 95% -1.40 to − 0.24, I2 = 88%, P = 0.005) and in those aged between 35 and 40 years (WMD -1.03, CI − 1.89 to − 0.17, I2 = 0%, P = 0.02). The number of metaphase II oocytes, miscarriage rates and live birth rates did not differ between the two groups of women overall or in subgroup analysis. Conclusion: Although more oocytes were retrieved in patients who underwent r-hFSH monotherapy, this meta-analysis suggests that r-hFSH/r-hLH co-treatment improves clinical pregnancy and implantation rates in women between 35 and 40 years of age undergoing ovarian stimulation for assisted reproduction technology. However, more RCTs using narrower age ranges in advanced age women are warranted to corroborate these findings. [ABSTRACT FROM AUTHOR]

Purpose: To assess whether the GnRH-agonist or urinary-hCG ovulation triggers affect oocyte competence in a setting entailing vitrified-warmed euploid blastocyst transfer. Methods: Observational study (April 2013–July 2018) including 2104 patients (1015 and 1089 in the GnRH-a and u-hCG group, respectively) collecting ≥1 cumulus-oocyte-complex (COC) and undergoing ICSI with ejaculated sperm, blastocyst culture, trophectoderm biopsy, comprehensive-chromosome-testing, and vitrified-warmed transfers at a private clinic. The primary outcome measure was the euploid-blastocyst-rate per inseminated oocytes. The secondary outcome measure was the maturation-rate per COCs. Also, the live-birth-rate (LBR) per transfer and the cumulative-live-birth-delivery-rate (CLBdR) among completed cycles were investigated. All data were adjusted for confounders. Results: The generalized-linear-model adjusted for maternal age highlighted no difference in the mean euploid-blastocyst-rate per inseminated oocytes in either group. The LBR per transfer was similar: 44% (n=403/915) and 46% (n=280/608) in GnRH-a and hCG, respectively. On the other hand, a difference was reported regarding the CLBdR per oocyte retrieval among completed cycles, with 42% (n=374/898) and 25% (n=258/1034) in the GnRh-a and u-hCG groups, respectively. Nevertheless, this variance was due to a lower maternal age and higher number of inseminated oocytes in the GnRH-a group, and not imputable to the ovulation trigger itself (multivariate-OR=1.3, 95%CI: 0.9–1.6, adjusted p-value=0.1). Conclusion: GnRH-a trigger is a valid alternative to u-hCG in freeze-all cycles, not only for patients at high risk for OHSS. Such strategy might increase the safety and flexibility of controlled-ovarian-stimulation with no impact on oocyte competence and IVF efficacy. [ABSTRACT FROM AUTHOR]

Study Question: Is there an association between patients' reproductive history and the mean euploidy rates per biopsied blastocysts (m-ER) or the live birth rates (LBRs) per first single vitrified-warmed euploid blastocyst transfers?Summary Answer: Patients' reproductive history (as annotated during counselling) showed no association with the m-ER, but a lower LBR was reported after euploid blastocyst transfer in women with a history of repeated implantation failure (RIF).What Is Known Already: Several studies have investigated the association between the m-ER and (i) patients' basal characteristics, (ii) ovarian stimulation strategy and dosage, (iii) culture media and conditions, and (iv) embryo morphology and day of full blastocyst development. Conversely, the expected m-ER due to women's reproductive history (previous live births (LBs), miscarriages, failed IVF cycles and transfers, and lack of euploid blastocysts among prior cohorts of biopsied embryos) still needs investigations. Yet, this information is critical to counsel new patients about a first cycle with preimplantation genetic testing for aneuploidy (PGT-A), but even more so after former adverse outcomes to prevent treatment drop-out.Study Design, Size, Duration: This observational study included all patients undergoing a comprehensive chromosome testing (CCT)-based PGT-A cycle with at least one biopsied blastocyst in the period April 2013-December 2019 at a private IVF clinic (n = 2676 patients undergoing 2676 treatments and producing and 8151 blastocysts). m-ER were investigated according to women's reproductive history of LBs: no/≥1, miscarriages: no/1/>1; failed IVF cycles: no/1/2/>2, and implantation failures after previous transfers: no/1/2/>2. Among the 2676 patients included in this study, 440 (16%) had already undergone PGT-A before the study period; the data from these patients were further clustered according to the presence or absence of euploid embryo(s) in their previous cohort of biopsied blastocysts. The clinical outcomes per first single vitrified-warmed euploid blastocyst transfers (n =1580) were investigated according to the number of patients' previous miscarriages and implantation failures.Participants/materials, Setting, Methods: The procedures involved in this study included ICSI, blastocyst culture, trophectoderm biopsy without hatching in Day 3, CCT-based PGT-A without reporting segmental and/or putative mitotic (or mosaic) aneuploidies and single vitrified-warmed euploid blastocyst transfer. For statistical analysis, Mann-Whitney U or Kruskal-Wallis tests, as well as linear regressions and generalised linear models among ranges of maternal age at oocyte retrieval were performed to identify significant differences for continuous variables. Fisher's exact tests and multivariate logistic regression analyses were instead used for categorical variables.Main Results and the Role Of Chance: Maternal age at oocyte retrieval was the only variable significantly associated with the m-ER. We defined five clusters (<35 years: 66 ± 31%; 35-37 years: 58 ± 33%; 38-40 years: 43 ± 35%; 40-42 years: 28 ± 34%; and >42 years: 17 ± 31%) and all analyses were conducted among them. The m-ER did not show any association with the number of previous LBs, miscarriages, failed IVF cycles or implantation failures. Among patients who had already undergone PGT-A before the study period, the m-ER did not associate with the absence (or presence) of euploid blastocysts in their former cohort of biopsied embryos. Regarding clinical outcomes of the first single vitrified-warmed euploid blastocyst transfer, the implantation rate was 51%, the miscarriage rate was 14% and the LBR was 44%. This LBR was independent of the number of previous miscarriages, but showed a decreasing trend depending on the number of previous implantation failures, reaching statistical significance when comparing patients with >2 failures and patients with no prior failure (36% versus 47%, P < 0.01; multivariate-OR adjusted for embryo quality and day of full blastocyst development: 0.64, 95% CI 0.48-0.86, P < 0.01). No such differences were shown for previous miscarriage rates.Limitations, Reasons For Caution: The sample size for treatments following a former completed PGT-A cycle should be larger in future studies. The data should be confirmed from a multicentre perspective. The analysis should be performed also in non-PGT cycles and/or including patients who did not produce blastocysts, in order to investigate a putative association between women's reproductive history with outcomes other than euploidy and LBRs.Wider Implications Of the Findings: These data are critical to counsel infertile couples before, during and after a PGT-A cycle, especially to prevent treatment discontinuation due to previous adverse reproductive events. Beyond the 'maternal age effect', the causes of idiopathic recurrent pregnancy loss (RPL) and RIF are likely to be endometrial receptivity and selectivity issues; transferring euploid blastocysts might reduce the risk of a further miscarriage, but more information beyond euploidy are required to improve the prognosis in case of RIF.Study Funding/competing Interest(s): No funding was received and there are no competing interests.Trial Registration Number: N/A. [ABSTRACT FROM AUTHOR]

An evidence-based novel commercially available continuous IVF culture medium in compliance with an efficient quality-management system is proposed. Non-interventional study on sibling oocytes. Intracytoplasmic sperm injection cycles among women aged 42 years or younger that used ejaculated spermatozoa and retrieved four to eight oocytes were included. Sibling oocytes were randomized for culture in the novel Geri-medium or continuous single culture medium (CSCM). Primary outcome measure was blastulation rate per cohort of inseminated oocytes; 1182 oocytes were required to outline down to a 7% difference (power = 80%). A total of 181 cohorts of sibling oocytes were included. Geri-medium (n = 631 oocytes) and CSCM (n = 643 oocytes) resulted in similar blastulation rates (mean ± SD: 42.8% ± 30.1% versus 43.1% ± 29.0%; Wilcoxon signed rank test = 0.77). Blastocysts cultured in the former (n = 275 versus n = 277) showed longer timings during preimplantation development (P < 0.01) and were poorer quality (26% versus 18%; P = 0.03). Euploidy rate was no different in cycles that underwent preimplantation genetic testing for aneuploidy (n = 113) (117/237 [49%] versus 117/249 blastocysts [47%]; P = 0.6). Ongoing implantation rate was comparable in the study arms after euploid (29/47 [63%] versus 14/ 34 [41%]; P = 0.1) or untested (12/31 [39%] versus 7/18 [39%]; P = 0.3) transfers. Blastulation rate among cohorts of sibling oocytes cultured in the same incubator is a fast, reliable and comprehensive performance indicator to validate novel commercially available culture medium. The media tested were considered similarly efficient. The differences in blastocyst morphology and developmental timings warrant further investigation, although euploidy and ongoing implantation rates were similar. [ABSTRACT FROM AUTHOR]

The transfer of cryopreserved blastocysts is increasing in IVF centres. However, little is known about the perinatal and obstetric outcomes of this procedure. In an attempt to further elucidate these issues, a systematic review and meta-analysis was conducted to compare cryopreserved transfer with fresh blastocyst embryo transfer. The results show that the risk of both preterm (odds ratio [OR] 0.89, 95% confidence interval [CI] 0.80–0.99, P = 0.04) and low birthweight births (OR 0.82, 95% CI 0.68–0.99, P = 0.04) was significantly lower after cryopreserved blastocyst transfer than after fresh blastocyst transfer. The rate of large for gestational age births was significantly higher (OR 1.68, 95% CI 1.55–1.82, P < 0.00001) and the rate of small for gestational age births significantly lower (OR 0.59, 95% CI 0.54–0.65, P < 0.00001) after cryopreserved blastocyst transfer. The transfer of cryopreserved blastocysts was associated with a significantly lower risk of placental abruption (OR 0.58, 95% CI 0.40–0.83, P = 0.003) but a significantly higher risk of Caesarean section (OR 1.21, 95% CI 1.01–1.43, P = 0.03). In conclusion, the perinatal and obstetric outcomes associated with the transfer of cryopreserved blastocysts differ from those associated with fresh blastocyst transfer. [ABSTRACT FROM AUTHOR]

Moreover, these oocytes were consistently reported similar for their fertilization, embryo development, embryo quality, euploidy (if assessed), implantation, miscarriage, and live birth rates. Similarly, Sfakianoudis I et al. i wrote 'DuoStim is correlated with a higher number of retrieved oocytes, mature MII oocytes, and good quality embryos in comparison to conventional stimulation. [Extracted from the article]