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Reproductive Medicine Center, The First Affiliated Hospital of Zhengzhou University, Zhengzhou, Henan, China, 2Henan Key Laboratory of Reproduction and Genetics, First Affiliated Hospital of Zhengzhou University, Zhengzhou, Henan, China Background: Optimal protocols for frozen-thawed embryo transfer (FET) after preimplantation genetic testing (PGT) remain unclear. This study compared Day 5 (D5) and Day 6 (D6) blastocysts and evaluated predictors of FET success. Methods: A total of 870 patients with genetic diseases or chromosomal translocations who received PGT at the First Affiliated Hospital of Zhengzhou University from January 2015 to December 2019 were recruited. All patients underwent at least one year of follow-up. Patients were divided into groups according to the blastocyst development days and quality. Univariate and multivariate logistic regression were applied to identify risk factors that affect clinical outcomes and to construct a predictive nomogram model. Area under the curve (AUC) of the subject's operating characteristic curve and GiViTI calibration belt were conducted to determine the discrimination and fit of the model. Results: D5 blastocysts, especially high-quality D5, resulted in significantly higher clinical pregnancy (58.4% vs 49.2%) and live birth rates (52.5% vs 45%) compared to D6. Multivariate regression demonstrated the number of blastocysts, endometrial preparation protocol, days of embryonic development and the quality of blastocysts independently affected live birth rates (P<0.05). A nomogram integrating these factors indicated favorable predictive accuracy (AUC=0.598) and fit (GiViTI, P=0.192). Conclusions: Transferring high-quality D5 euploid blastocysts after PGT maximizes pregnancy outcomes. Blastocyst quality, blastocyst development days, endometrial preparation protocols, and number of blastocysts, independently predicted outcomes. An individualized predictive model integrating these factors displayed favorable accuracy for counseling patients and optimizing clinical management. [ABSTRACT FROM AUTHOR]

In conclusion, we recommend patients consider inactivated COVID-19 vaccination before commencing IVF/ICSI treatments to reduce the risk of SARS-CoV-2 infection and severe symptoms during pregnancy that may threaten the well-being of both pregnant mothers and their unborn children. Here, the biochemical pregnancy rates, clinical pregnancy rates and early miscarriage rates were not affected by the vaccination status. Effects of COVID-19 vaccination status, vaccine type, and vaccination interval on IVF pregnancy outcomes in infertile couples. Effects of inactivated COVID-19 vaccinations on the IVF/ICSI-ET live birth rate and pregnancy complication in a population of southern China: A retrospective cohort study. [Extracted from the article]

Biallelic variants in Cystic Fibrosis Transmembrane Conductance Regulator (CFTR) are the main pathogenic factor of congenital absence of the vas deferens (CAVD), including congenital bilateral absence of the vas deferens (CBAVD) and congenital unilateral absence of the vas deferens (CUAVD). However, there are few reports about the correlation between CFTR variant and outcomes of assisted reproductive technology (ART) in CAVD patients of China. In this study, 104 patients with CAVD were recruited in Central China, and provided gene detection by the whole-exome sequencing, among them 69% (72/104) carried at least one variant in CFTR and one carried adhesion G protein-coupled receptor G2 (ADGRG2) variant. A total of 81 CAVD patients were treated with ART, of which 21 and 60 carried none or at least one variant in CFTR, respectively. The fertilization rate, cleavage rate, effective embryo rate, implantation rate, clinical pregnancy rate and live birth rate per fresh embryo transfer were compared between patients with and without CFTR variants. It was found that the ART outcomes had no significant difference whether the patients carried the CFTR variant or not. In addition, all of the offspring were healthy after follow-up. In conclusion, rare CFTR variants may play a major role in patients with CAVD in Central China, which were greatly different from other descent. There was no significant difference in ART outcomes in CAVD patients with or without CFTR variants. The limitations of this study were that there was no statistical analysis of the sperm quality through TESA and conclusions were relatively limited due to the small sample size of the study. [ABSTRACT FROM AUTHOR]

Background: To compare the efficacy and safety of follitropin delta in its individualized fixed-dose regimen with follitropin alfa in a conventional adjustable dosing regimen in Chinese women. Methods: This was a subgroup analysis of the randomized, multi-center, assessor-blind, non-inferiority trial (GRAPE) including 759 Chinese women (aged 20–40 years) recruited in 16 reproductive medicine clinics in China. Women were randomized in a 1:1 ratio to be treated with either follitropin delta dose based on anti-Müllerian hormone (AMH) and body weight or conventional dosing with follitropin alfa following a gonadotropin-releasing hormone (GnRH) antagonist protocol. The primary outcome was ongoing pregnancy rate assessed 10–11 weeks after embryo transfer in the fresh cycle (non-inferiority margin -10.0%). Results: 378 in the follitropin delta group and 381 in the follitropin alfa group were randomized and exposed. Non-inferiority was confirmed with respect to ongoing pregnancy with rates of 31.0% vs. 25.7% for follitropin delta compared to follitropin alfa, estimated mean difference of 5.1% (95% confidence interval (CI) -1.3% to 11.5%). The clinical pregnancy rate (35.4% vs. 31.5%, P = 0.239) and live birth rate (31.0% vs. 25.5%, P = 0.101) were comparable between the follitropin delta group and the follitropin alfa group. Overall, the individualized follitropin delta treatment resulted in fewer oocytes retrieved compared to follitropin alfa treatment (10.3 ± 6.2 vs. 12.5 ± 7.5, P < 0.001), which was mainly due to fewer oocytes (10.5 ± 6.4 vs. 13.9 ± 7.8) in women with AMH ≥ 15 pmol/L. Accordingly there was a lower incidence of early ovarian hyper-stimulation syndrome (OHSS) and/or preventive interventions (6.1% vs. 11.0%, P = 0.013). A daily follitropin delta dose of 10.2 µg (95% CI: 9.3—11.2 µg) was estimated to provide the same number of oocytes retrieved as a starting dose of 150 IU/d of follitropin alfa. Conclusion: Follitropin delta in its individualized fixed-dose regimen showed similar efficacy and improved safety compared with follitropin alfa in a conventional adjustable dosing regimen in Chinese women. Clinical trial registration number: NCT03296527. [ABSTRACT FROM AUTHOR]

Study Question: Does dual trigger in freeze-all in vitro fertilization (IVF)/intracytoplasmic sperm injection (ICSI) cycles improve the cumulative live-birth outcome compared with human chorionic gonadotropin (hCG) trigger? Summary Answer: Dual trigger for final follicular maturation improves the cumulative pregnancy and live-birth rates compared with hCG trigger in freeze-all IVF/ICSI cycles. What Is Known Already: Dual trigger could increase the numbers of oocytes and mature oocytes and improve pregnancy rates. Study Design, Size, Duration: This retrospective cohort analysis included data from 4438 freeze-all IVF/ICSI cycles between January 2012 and December 2017. Participants/Materials, Setting, Methods: Women aged 20−49 years who underwent ovarian stimulation and oocyte retrieval for autologous IVF/ICSI with a freeze-all policy in our centre were enrolled. Data on number of oocytes retrieved, number of mature oocytes, clinical pregnancy rate, live-birth rate, cumulative pregnancy rate, and cumulative live-birth rate (CLBR) were assessed and compared between patients who underwent a dual trigger and hCG trigger. Multivariate logistic regression was performed to identify and adjust for factors known to independently affect the CLBR. Main Results and the Role of Chance: A total of 4438 IVF/ICSI cycles were analyzed, including 1445 cycles with single hCG trigger and 2993 cycles with dual trigger. The cumulative biochemical pregnancy rate (60.8% vs. 68.1%, P<0.001; odds ratio (OR): 0.727; 95% confidence interval (CI): 0.638–0.828), cumulative clinical pregnancy rate (52.9% vs. 58.5%, P<0.001; OR: 0.796; 95%CI: 0.701–0.903), and CLBR (44.3% vs. 50.5%, P<0.001; OR: 0.781; 95%CI: 0.688–10.886) were all significantly lower in the hCG-trigger group compared with the dual-trigger group. The clinical pregnancy rate (48.2% vs. 58.2%, P=0.002; OR: 0.829; 95%CI: 0.737–0.934) and embryo implantation rate (34.4% vs. 38.9%, P<0.001; OR: 0.823; 95%CI: 0.750–0.903) in each transfer cycle were also significantly lower in the hCG-trigger group compared with the dual-trigger group. After controlling for all potential confounding variables, the trigger method was identified as an independent factor affecting the CLBR. The OR and 95%CI for hCG trigger were 0.780 and 0.641–0.949 (P=0.013). Limitations, Reasons for Caution: The data used to analyse the effect of dual trigger on cumulative pregnancy and live-birth outcomes were retrospective, and the results may thus have been subject to inherent biases. Further prospective randomized controlled trials are required to verify the beneficial effects of dual trigger. Wider Implications of the Findings: Dual trigger had a positive effect on CLBRs, suggesting that it could be used as a routine trigger method in freeze-all cycles. Study Funding/Competing Interest(s): This study was supported by grants from National Key Research and Development Program of China (2018YFC1004800), the Natural Science Program of Zhejiang (LY19H040009), the National Natural Science Foundation of China (No. 81601236). No authors have competing interests to declare. [ABSTRACT FROM AUTHOR]

Study Question: Is there an association between peak serum estradiol (E2) level during controlled ovarian stimulation (COS) and neonatal birthweight in freeze-all cycles?Summary Answer: Peak serum E2 level during ovarian stimulation is not associated with neonatal birthweight in freeze-all cycles.What Is Known Already: Supraphysiologic E2 levels during COS have been demonstrated to generate a suboptimal peri-implantation endometrial environment and thus lead to adverse neonatal outcomes in fresh embryo transfer cycles. Previous experimental studies also suggested a potential influence of superovulation on oocyte epigenetic programming, but whether it translates into altered phenotypes of fetal growth and development remains unclear in clinical practice. By segmenting the process of COS and embryo transfer, the freeze-all policy provides a novel model to investigate the sole impact of ovarian stimulation on oocytes after ruling out the effects of hyperestrogenic milieu on endometrium in fresh cycles.Study Design, Size, Duration: A retrospective cohort study of 8501 patients who underwent their first COS cycles with a freeze-all strategy and delivered live-born singletons in subsequent frozen-thawed embryo transfer cycles from January 2007 to December 2016 at a tertiary-care academic medical center.Participants/materials, Setting, Methods: Patients were categorized into six groups according to E2 level on trigger day in regular increments of 1000 pg/mL: <1000, 1000-1999, 2000-2999, 3000-3999, 4000-4999 and ≥5000 pg/mL. Univariable and multivariable linear regression and logistic regression analysis were performed to assess the independent association between peak E2 level and measures of neonatal birthweight including absolute birthweight, Z-score, low birthweight (LBW) and small-for-gestational age (SGA).Main Results and the Role Of Chance: The six groups did not differ significantly in birthweight, Z-score or the incidence of LBW and SGA. Compared with the E2 <1000 pg/mL group, the adjusted mean difference (95% confidence interval [CI]) of stratified higher E2 groups was 17.2 (-31.0-65.5), 12.3 (-35.9-60.5), -4.1 (-51.9-43.7), -0.6 (-48.9-47.8) and -3.6 (-50.0-42.8) g for birthweight, and 0 (-0.11-0.10), 0.02 (-0.08-0.12), 0.04 (-0.06-0.14), -0.01 (-0.11-0.10) and -0.04 (-0.14-0.06) for Z-score, respectively. Regarding the outcomes of LBW and SGA, no increased risks were observed in each E2 category, with the adjusted odds ratio (95% CI) being 1.21 (0.68-2.16), 1.0 (0.58-1.90), 0.90 (0.50-1.63), 0.93 (0.51-1.69) and 1.08 (0.61-1.90) for LBW, and 0.97 (0.58-1.64), 1.06 (0.63-1.77), 0.77 (0.46-1.31), 0.71 (0.41-1.22) and 1.00 (0.60-1.65) for SGA, respectively.Limitations, Reasons For Caution: The study was retrospective in design, and other unknown confounding factors may not be included for adjustment. Furthermore, the generalization of the study finding could be limited to some extent by the majority of double cleavage-stage embryo transfer and difference in birthweight reference percentiles between Chinese and other populations.Wider Implications Of the Findings: Our observations suggest that the hyperestrogenic milieu during COS does not seem to pose adverse effects on neonatal birthweight after frozen-thawed embryo transfer, which provides reassuring information for high ovarian responders in freeze-all cycles concerning their offspring's health.Study Funding/competing Interest(s): This study was funded by the National Key Research and Development Program of China (SQ2018YFC100163) and National Natural Science Foundation of China (81571397, 81771533). The authors declare no conflict of interest. [ABSTRACT FROM AUTHOR]

Objective: To investigate whether supraphysiological estradiol (E2 ) in controlled ovarian stimulation (COS) cycles affects the subsequent frozen-thawed embryo transfer (FET) in terms of the neonatal birthweight.Design: Retrospective cohort study.Setting: University affiliated hospital.Population: In all, 2066 patients undergoing FET cycles that resulted in live singleton births between July 2011 and Dec 2016.Interventions: None.Methods: Multivariable linear regression and logistic regression was used to evaluate the association between peak E2 and birthweight outcomes.Main Outcome Measures: Birthweight, z-score adjusted for gender and gestational age, and incidence of small-for-gestational-age (SGA) and low birthweight (LBW) in singleton neonates derived from FET cycles.Results: Adjusted for confounding factors, both the absolute birthweight and the z-score of singletons following FET were negatively associated with peak E2 levels in COS. In comparison with the referent category (E2  ≤1500 pg/ml), the categories with E2  >3000 pg/ml had a significantly lower z-score. The difference (95% CI) in estimated marginal mean of birthweights between referent category and highest E2 (>8000 pg/ml) category was 104.57 g (18.13-181.06). Multiple logistic regression analyses showed that the adjusted odds ratio (95% CI) for SGA and LBW in term singletons comparing patients with E2  >3000 pg/ml with those with E2  ≤3000 pg/ml was 2.44 (1.37-4.34) and 2.32 (1.01-5.40), respectively.Conclusions: Peak E2 levels in COS cycles are negatively associated with the birthweight of singletons conceived through subsequent FET cycles.Tweetable Abstract: The birthweight following FET is affected by previous COS cycle. [ABSTRACT FROM AUTHOR]

Objective: To evaluate the impact of assisted reproductive technology (ART) on the offspring of Chinese population.Design: Retrospective, data-linkage cohort.Setting: Not applicable.Patient(s): Live births resulting from ART or natural conception.Intervention(s): None.Main Outcome Measure(s): Birth defects coded according to ICD-10.Result(s): Births after ART were more likely to be female and multiple births, especially after intracytoplasmic sperm injection (ICSI). ART was associated with a significantly increased risk of birth defects, especially, among singleton births, a significantly increased risk in fresh-embryo cycles after in vitro fertilization (IVF) and frozen-embryo cycles after ICSI. Associations between ART and multiple defects, between ART and gastrointestinal malformation, genital organs malformation, and musculoskeletal malformation among singleton births, and between ART and cardiac septa malformation among multiple births were observed.Conclusion(s): This study suggests that ART increases the risk of birth defects. Subgroup analyses indicate higher risk for both fresh and frozen embryos, although nonsignificantly for frozen embryos after IVF and for fresh embryos were presented with low power. Larger sample size research is needed to clarify effects from fresh- or frozen-embryo cycles after IVF and ICSI. [ABSTRACT FROM AUTHOR]

Objective: To evaluate the effect of frozen embryo transfer on maternal and neonatal complications of singleton and twin pregnancies compared with fresh embryo transfer in women with polycystic ovary syndrome (PCOS).Design: A secondary analysis of a multicenter, randomized, controlled trial comparing live birth after frozen vs. fresh embryo transfer (FreFro-PCOS).Setting: Reproductive medicine centers.Patient(s): A total of 1,508 patients with a diagnosis of PCOS who were undergoing IVF were enrolled.Intervention(s): On day of oocyte retrieval, eligible patients were randomized to the fresh or frozen embryo transfer groups. Up to two embryos were transferred in both groups. All pregnancies were followed up until delivery.Main Outcome Measure(s): Gestational diabetes mellitus, pre-eclampsia, preterm birth, small for gestational age, and large for gestational age.Result(s): The risks of gestational diabetes mellitus, preterm birth, and small for gestational age were comparable between the frozen and fresh embryo transfer groups in both singleton and twin births. However, singleton infants born after frozen embryo transfer were more likely to be large for gestational age (25.2% vs. 17.5%; relative risk 1.44, 95% confidence interval 1.01-2.07, P=.044) than those born after fresh embryo transfer. Twin pregnancy after frozen embryo transfer had a higher risk of pre-eclampsia (12.0% vs. 2.8%; relative risk 4.31, 95% confidence interval 1.27-14.58, P=.009) than those after fresh embryo transfer.Conclusion(s): In women with PCOS, frozen embryo transfer resulted in an increased risk of large for gestational age in singleton pregnancy and a higher risk of pre-eclampsia in twin pregnancy.Clinical Trial Registration Number: NCT01841528. [ABSTRACT FROM AUTHOR]

Objective: To investigate infertility patients' attitudes towards frozen embryos and the factors that influence patients' decisions.Study Design: This is a cross-sectional quantitative observational study conducted between 1 April 2010 and 1 April 2015. Patients underwent IVF with embryo cryopreservation and successfully delivered at least one baby were called to complete a questionnaire regarding decisions about embryo disposition and reasons for their preferred option. The chi-square test was used to compare the attitudes about embryo disposition between subgroups. A multinomial logistic regression was performed to examine the effects of various individual characteristics on the decision. The effects were presented by adjusted odds ratios (OR) and their 95% confidence interval (95% CI).Setting: Guangzhou Women and Children's Hospital.Results: Among 769 interviewed couples, 718 couples (93.4%) completed the questionnaire. A total of 462 couples (64.3%) continued to store embryos. Among the participants who discontinued storage, 214 couples (83.6%) chose to discard embryos, and 42 couples (16.4%) agreed to donate embryos for research. Having no college education and longer storage duration were associated with an increase in the likelihood of discontinuing storage. The couples having twins from IVF were more likely to discontinue storage (OR=6.33, 95%CI: 4.37-9.39) compared to those having only one child. Regarding the choice of discarding or donation for research among those who decided to discontinue frozen embryos, females aged 30 or above were more willing to donate their embryos for research (OR=2.85, 95%CI:1.12-7.23).Conclusion: The preference for embryo disposition was associated with the number of children, storage duration, and the couple's education. Chinese patients generally chose to store cryopreserved embryos and were less receptive to the concept of embryo research compared with patients in other developed countries. [ABSTRACT FROM AUTHOR]

Background: Multiple pregnancies are one of the major safety concerns of in vitro fertilization (IVF) due to the increased risk of maternal and neonatal complications. Single embryo transfer is the most effective way to reduce the risk of multiple pregnancies. Selection of the embryo and optimization of the implantation environment are crucial to retain the success rate when the number of transferred embryos is diminished. Fresh embryo transfer with supra-physiological levels of hormones has been suggested to have an adverse effect on implantation. Elective frozen embryo transfer has been suggested to result in a higher rate of live birth than fresh embryo transfer. However, there is still a lack of evidence from randomized clinical trials comparing the efficacy and safety between frozen and fresh single blastocyst transfers.Methods/design: We are conducting a randomized controlled trial in women aged 20-35 undergoing their first cycle of IVF with or without intracytoplasmic sperm injection. After ovarian stimulation with a gonadotropin-releasing hormone antagonist protocol, women who obtain four or more embryos on day 3 of the embryo culture are randomized into two parallel groups: a single fresh blastocyst transfer group and a single frozen blastocyst transfer group (all blastocysts vitrified and a deferred frozen blastocyst transfer). The primary outcome is singleton live birth.Discussion: The results of this study will provide evidence for the efficacy and safety of the strategy of elective frozen single blastocyst transfer in women with a good prognosis.Trial Registration: Chinese Clinical Trial Registry, ChiCTR-IOR-14005405 . Registered on 30 Oct 2014. [ABSTRACT FROM AUTHOR]

Objective: To evaluate the effects of recombinant human growth hormone (rhGH) on clinical outcomes of frozen-thawed embryo transfer (FET).Methods: A prospective study was conducted among 240 patients (aged ≤38years) who underwent FET cycles at a center in Hefei, China, between November 2011 and October 2012. Patients were divided into three groups on the basis of visit order: those in group A received hormone-replacement therapy (HRT) for endometrial preparation, those in group B received HRT plus simultaneous rhGH, and those in group C received rhGH on day8 of HRT.Results: Ten cycles were cancelled; 230 FET cycles were analyzed (77 in group A, 77 in group B, 76 in group C). The rates of clinical pregnancy, embryo implantation, and live birth were significantly higher in group B than in group A, as were the serum levels of estradiol and insulin-like growth factor-1 (P≤0.033 for all comparisons). Endometrial thickness and serum levels of vascular endothelial growth factor were significantly higher in group B than in groups A and C, whereas pulsatility index, resistance index, and peak systolic velocity/end diastolic velocity of the uterine arcuate artery were significantly lower (P≤0.017 for all comparisons).Conclusion: Simultaneous administration of rhGH with HRT could improve clinical outcomes after FET by increasing endometrial blood perfusion and expression of cytokines related to endometrial receptivity. [ABSTRACT FROM AUTHOR]

STUDY QUESTION What is the association between the number of oocytes retrieved and the live birth rate (LBR) following first IVF treatment cycles in China? SUMMARY ANSWER In first IVF treatment cycles, the LBR after fresh transfer was maximal in the groups with 6–10 or 11–15 oocytes and reduced in the groups with 0–5 or >15 oocytes. Despite this, the cumulative LBR after including frozen embryo transfer cycles increased with an ovarian response. WHAT IS KNOWN ALREADY There is a strong association between oocyte number and IVF outcome; however, this is a comprehensive analysis conducted to investigate the relationship between oocyte number and fresh cycle as well as cumulative LBRs in first IVF treatment cycles. STUDY DESIGN, SIZE AND DURATION This is a large retrospective cohort study (n = 2455); patients were categorized into four groups according to the number of oocytes retrieved (0–5, 6–10, 11–15 and >15 oocytes). The fresh embro transfer LBR and cumulative LBR were evaluated by group. Univariate analysis was performed to identify factors that predict the chance of LBR. Multivariate logistic regression was used to assess the association between oocyte number and LBR after adjusting for confounding factors that were identified as significant in the univariate analysis. PARTICIPANTS/MATERIALS, SETTING AND METHODS A total of 2455 women who were undergoing their first IVF treatment cycle at the Reproductive Medicine Center of Anhui Provincial Hospital, P.R. China from April 2007 to December 2011 were identified and reviewed. All patients had normal menstrual cycles and were stimulated with a long GnRH agonist protocol. Associations between oocyte number and LBR and miscarriage rate as well as the rate of moderate-severe ovarian hyperstimulation syndrome (OHSS) were analyzed. MAIN RESULTS AND ROLE OF CHANCE The fresh embryo LBR per started cycle increased with the number of retrieved oocytes up to Groups 2 and 3 (6–10 and 11–15 oocytes) and then decreased, because of the high number of cycles with all embryos being cryopreserved, in order to avoid moderate–severe OHSS in group 4 (>15 oocytes). However, the cumulative LBR per started cycle continued to increase with oocyte number, as did the incidence of moderate–severe OHSS. There was no significant difference in the miscarriage rates among the patient groups. LIMITATIONS, REASONS FOR CAUTION As a retrospective study, our analysis depends on previously recorded data; therefore, certain variables could not be collected. Our findings may be influenced by our young and thin patient population and the inability to control for certain markers of ovarian reserve such as historical maximum serum FSH, antral follicle count and serum anti-Mullerian hormone. WIDER IMPLICATIONS OF THE FINDINGS Our data suggest that in IVF cycles stimulated with a long protocol, the optimal number of oocytes for achieving a live birth is somewhere between 6 and 15. The balance between maximum treatment success and minimum risk of complications, especially OHSS, should be further investigated. STUDY FUNDING/COMPETING INTERESTS This study was supported by the Medical Scientific Research Plan Project of Anhui Provincial Department of Health (13ZC014) and the Natural Science Foundation of Anhui Higher Education Institutions (KJ2013Z132). [ABSTRACT FROM AUTHOR]

Purpose: To analyze the clinical outcomes of frozen embryo transfer (FET) cycles when two or three multicellular embryos were transferred in Chinese women. Methods: A retrospective study was conducted to analyze 980 FET cycles performed between January 2007 and October 2010. Two (785 cycles) or three (195 cycles) multicellular embryos were transferred. Results: Both in patients under 35 years ( n = 776) and those aged 35 to 39 years ( n = 169), the transfer of two versus three multicellular embryos results in similar clinical pregnancy rates (CPR), implantation rates (IR) and live birth rates (LBR). In both age groups, the multiple pregnancy rate (MPR) was significantly higher in the three-embryo groups. Among women over 40 years of age ( n = 35), there were no differences in the CPR, IR, MBR or LBR between the two groups Conclusions: Transferring two instead of three multicellular embryos in patients under 40 years old significantly decreases the risk of MPR without compromising PR, IR and LBR. In the age group above 40, transferring two instead of three multicellular embryos did not decrease PR, IR, MBR or LBR. Transferring more embryos when a patient had more unsuccessful cycles was not warranted in all patients. [ABSTRACT FROM AUTHOR]

Objective: To investigate flexibility in starting controlled ovarian stimulation at any phase of the menstrual cycle in infertile women undergoing treatment with assisted reproduction.Design: Retrospective cohort study.Setting: Academic tertiary-care medical center.Patient(s): At total of 150 infertile patients undergoing in vitro fertilization (IVF) or intracytoplasmic sperm injection (ICSI) treatment. Ninety of the women also underwent frozen embryo transfer (FET) procedures.Intervention(s): Depending on the phase of the menstrual cycle when ovarian stimulation was started, three groups of patients were identified, namely: conventional group (ovarian stimulation started in the early follicular phase), late follicular phase group, and luteal phase group. When dominant follicles were observed, final oocyte maturation was triggered with the use of GnRH agonist and hCG. In all three groups, viable embryos were cryopreserved for subsequent transfer.Main Outcome Measure(s): Primary Outcome: number of mature oocytes retrieved.Secondary Outcomes: fertilization rate, viable embryo rate per oocyte retrieved, cancellation rate, and clinical pregnancy outcomes from FET cycles.Results(s): There were no differences in the mean number of mature oocytes retrieved in the conventional group, late follicular phase group, and luteal phase group (5.7 ± 3.6, 5.2 ± 3.7, and 5.2 ± 3.9, respectively). Similarly, no significant differences were observed in the viable embryo rate per oocyte retrieved (37.9%, 38.5%, and 43.6%), clinical pregnancy rates (41.5%, 45.5%, and 38.9%), and implantation rates (30.7%, 30.2%, and 27.1%) in the three groups.Conclusion(s): All three ovarian stimulation protocols were observed to be equally effective. These results demonstrate that ovarian stimulation can be commenced on any day of the menstrual cycle.Clinical Trial Registration Number: ChiCTR-OPN-15007332. [ABSTRACT FROM AUTHOR]