Search

Thrombophilia is a group of inherited or acquired coagulation disorders that have been associated with reproductive failure. However, there are still no clear recommendations on whether its inclusion in the initial study of the infertile couple or patients with recurrent implantation failure is necessary. In this discussion paper, based on a SWOT (strengths, weaknesses, opportunities, threats) analysis, the different aspects of the repercussions of thrombophilia screening and treatment in reproduction are evaluated. To avoid possible subjectivity in the analysis and results of this study, researchers followed Oxford criteria for the evaluation of evidence. The results from the evaluation of the reviewed bibliography seem to indicate that, pending new evidence, it would be advisable not to include thrombophilia screening in the initial baseline study of the infertile couple. There is no evidence to support a clear association between thrombophilia and implantation failure or infertility. Thrombophilia testing in this setting may increase cost, with minimal potential benefit and lead to inappropriate use of anticoagulants with possible deleterious adverse effects. Future well-designed studies are needed to assess the possible benefit of anticoagulant therapy in infertile thrombophilic patients with implantation failure.

Chronic endometritis is a pathology often associated with reproductive failure, but there are still no clear recommendations on whether its inclusion in the initial study of infertile couples is necessary. In this discussion paper, based on a SWOT (Strengths, Weaknesses, Opportunities, Threats) analysis, the different aspects of the repercussions of chronic endometritis in fertility are evaluated. To avoid possible subjectivity in the analysis and results of this study, the researchers followed the Oxford criteria for the evaluation of evidence. The results from the evaluation of the reviewed literature seem to indicate that, pending new evidence, it would be advisable not to include chronic endometritis in the initial baseline study before assisted reproduction in order not to delay other assisted reproduction treatments. However, it would be advisable in cases of repetitive implantation failure and pregnancy loss after having undergone IVF with viable embryos and before continuing with costly reproductive processes, since results could be improved. The development of randomized studies assessing the impact of antibiotic treatment as a possible therapeutic option in infertile women with chronic endometritis, as well as the possible impact on endometrial microbiota and receptivity/implantation, would allow for the establishment of more precise clinical guidelines in this regard.

The main barrier for an appropriate primary management of the reproductive health was lack of knowledge about the risk factors and prevention measures for infertility and the main recommendations was to involve primary care physicians in reproductive health. To reach a consensus around barriers and enablers for appropriate primary management of the reproductive health. An observational study was performed using the modified Delphi technique, from October 2017 to April 2018 in private and public assisted reproduction clinics in Spain. A questionnaire consisted of 58 items, divided into four blocks to explore consensus among a group of experts by synthesizing opinions. In the first Delphi round, the response rate was 50% and panelists reached a 72.4% of consensus. In second round, the response rate was 55% and panelists reached a 25% of consensus. To minimize limitations related to the use of a structured questionnaire, a space for free text responses was provided. The following items yielded unanimous agreement: “It is necessary to promote reproductive planning—not just contraception—from secondary school,” “The media should not trivialize pregnancies in women aged over 50,” “Postponing family formation is the main cause of the increase in assisted reproduction treatments in Spain,” and “Postponing motherhood implies an inherently decreased probability of having children.” These recommendations could set the basis for a public health action plan for primary management of reproductive health. The findings may be applicable to any country whose health services system provides primary healthcare.

To study uterine peristalsis using step-by-step 4-dimensional (4D) ultrasound assessment video, explore its relationship with progesterone levels in a select in vitro fertilization population, and assess the reproducibility of the technique.Four-dimensional uterine ultrasound and a retrospective analysis of outcomes in relation with progesterone levels. The videos were also analyzed by a senior doctor, junior doctor, and a nurse for their reproducibility.Instituto Bernabeu of Alicante is a private clinic.The study included 197 consecutive patients undergoing in vitro fertilization (from 2018 to 2019) with a history of recurrent implantation failure (defined as unsuccessful implantation of a total number of ≥3 blastocysts originated from oocyte donation cycles). Because it is known that most failures are attributed to the quality of the embryo, we deemed it important to explore the potential uterine factors explaining the failures in oocyte donation cycles, the use of which decreases the probability of embryo-related factors influencing it.The participants were evaluated for uterine contractions and serum progesterone levels (10-30 minutes before the embryo transfer procedure). Uterine contractility (UC) was assessed by recording a 6-minute-long video using a 4D mode (Voluson E10; General Electric, Boston, MA), which was performed by a single operator (B.M.).The contractions were seen like waves going through the endometrial cavity. They were counted on a ×15 accelerated recording video. To define high-frequency UC, we separated uterine peristalsis (contractions per minute [cpm]) into quartiles. The highest quartile defined the hypercontractility group (1.51 cpm; n = 41), considering the remaining quartiles as the normal contractility group (≤1.51 cpm; n = 156). The Mann-Whitney U test was performed. The intraclass correlation coefficient was used to validate variability. P.05 was considered significant. SPSS version 21.0 was used for the statistical analysis. The institutional review board's approval was obtained.Overall, an average of 1.1 cpm was found in the study population. There were no differences between the groups (hypercontractility vs. normal contractility) in terms of patient age and the presence of any uterine factor (adenomyosis, myomas, adhesions, or polyps). An inverse association was observed between UC and progesterone levels. Low progesterone levels (15.9 vs. 19.5 ng/mL; P = .027) were observed in the HUP and NUP group, respectively. The intraclass correlation coefficient to evaluate the interobserver variability was 0.75 (0.63-0.85; P = .000).Four-dimensional ultrasound assessment provides a dynamic view of uterine contractions, including their directionality and frequency. Even though recurrent implantation failure is yet a title of obscure definition and probably associated with multiple factors, a subgroup of patients with elevated UC associated with "low" progesterone levels may have a potential effect on their outcomes. Four-dimensional scan evaluation of UC constitutes a promising diagnostic tool in clinical practice; however, larger studies confirming our initial results are still pending.

Objective: Twisted uterus is detected when the body of the uterus is rotated from the cervical canal. This anomaly may be due to different causes, such as uterine fibroids, endometriosis or the presence of both. The study has aimed to compare the effect of the twisted uterus cause in terms of reproductive treatment outcomes. Materials and methods: It consisted of a retrospective study of twisted uterus cases with repeated implantation failure (more than three embryo transfers or four blastocysts transferred unsuccessfully) in our ultrasound department. The twisted uterus was defined when the vaginal probe needed to be rotated to assess the endometrial line thoroughly or when the coronal view was seen by 2D scan. From 2017 to 2020, 879 gynecological ultrasounds were performed. For statistical analysis, we carried out a logistical regression analysis adjusted by confounding factors. Results: From 145 patients included only 92 patients underwent reproductive treatments. With the known cause of uterine torsion. 56 patients with endometriosis, 18 with uterine myoma and the remaining 18 suffered from both. After assisted reproductive treatment, the endometriosis group showed the highest clinical pregnancy rate (53.57%) compared to myoma (22.22%) and endometriosis and myoma (38.89%) groups. Conclusion: Uterine myoma capable of causing uterine torsion may affect embryo implantation more than endometriosis. Prospective randomized studies with a larger number of patients would be needed to confirm these findings.

Background In young women with poor ovarian response, luteal-phase ovarian stimulation (LPOS) is a potential method for collecting competent oocytes. The aim of this study was to assess the efficacy of LPOS compared with follicular phase ovarian stimulation (FPOS) in young women with poor ovarian response (POR). Methods This single-center, prospective, randomized pilot study compared LPOS and FPOS in women with POR fulfilling Bologna criteria who underwent in vitro fertilization at the Instituto Bernabeu. The primary outcome was the number of metaphase II (MII) oocytes obtained by follicular puncture. Results Sixty women were included in the study, with 27 women completing LPOS and 30 undergoing FPOS. There was no statistically significant difference in the number of MII oocytes obtained between the LPOS group and the FPOS group (2.1 ± 2.0 vs. 2.6 ± 2.2, p = 0.31). Length of stimulation was also similar in both groups (8.35 ± 2.8 vs. 8.15 ± 4.1 days, p = 0.69). Similarly, there was no significant difference in the follicle-stimulating hormone total dose, number of cumulus-oocyte complexes, survival rate, fertilization rate, or cancellation rate between groups. A significantly higher Ovarian Sensitivity Index was observed in the LPOS group versus the FPOS group (0.96 vs. 0.57, p = 0.037). Conclusion LPOS was comparable with FPOS in terms of efficacy and may improve ovarian responsiveness in young women with POR. Trial registration ClinicalTrials.gov identifier: NCT02625532; EudraCT identifier: 2015–003856-31.

Objective To investigate if polymorphisms of some genes involved in folliculogenesis predict ovarian response. Methods This prospective randomized study includes 124 egg donors genotyped for six SNPs ESR1 (rs2234693), AMHR2 (rs2002555), GDF-9 (rs10491279 and rs254286), AMH (rs10407022) and LHCBR (rs229327) genes and four STRs in ESR1 rs3138774), SHBG (rs6761), CYP19A1 (rs60271534) and AR genes (CAG repeats in exon 1). All donors followed standard ovarian stimulation protocol using a daily dose of 225 UI. The genotypes obtained were compared with the ovarian stimulation outcome. Results Regarding the number of retrieved oocytes, we found statistical differences for the ESR1 SNP and STR (19.3 ± 8.9 for TT vs 15.3 ± 6.2 for CC/CT, P = 0.027; 19.1 ± 8.3 for 17repeats, P = 0.020). Moreover, women carrying TT in the ESR1 at position c.-397T>C with ESR1 (TA)n=17 retrieved the highest number of oocytes (20.4 ± 9.3) (P = 0.001). Concerning AMHR2, we observed an association with the length of stimulation (9.1 ± 1.4 d for AA vs 9.7 ± 1.3 d for AG/GG, P = 0.021) and gonadotropin received (2050 ± 319 for AA vs 2188 ± 299 for AG/GG, P = 0.017). No significant differences were observed for the other polymorphisms (P > 0.05). Conclusion The polymorphisms in ESR1 and AMHR2 genes showed a clear association with the number of retrieved oocytes and the stimulation data, respectively. Our results suggest that polymorphisms in the genes for key reproductive hormones receptors could be used to predict the ovarian response and to personalize the stimulation prior the treatment.

Study question Does the follicle-stimulating hormone receptor (FSHR) genotype influence the results of the ovarian stimulation treatment in the luteal phase? Summary answer All patients undergoing in-vitro fertilization benefit from luteal phase ovarian stimulation, regardless of their follicle-stimulating hormone receptor genotype. What is known already Previous studies suggest that FSH receptor polymorphism in position 680 influences the response to ovarian stimulation in the luteal phase. It was observed that patients with SS genotype seems to require a higher dose to obtain an optimal ovarian response. Later, it was reported that, in patients with SS genotype, a better performance seems to be obtained by administering highly purified urinary FSH while, in SN patients, better results were obtained with recombinant FSH. In patients with NN genotype, no differences were found. Our aim was to test whether this concept is applicable to ovarian stimulation in the luteal phase. Study design, size, duration One hundred and thirty-four patients were included in a retrospective study between July 2017 and September 2020. In these patients, a double stimulation protocol was carried out and the FSH receptor was genotyped either as part of the pre-treatment fertility tests or for the current study. Patients with a double stimulation treatment who could not be genotyped were excluded from the analysis. Participants/materials, setting, methods To genotype the 680 position of the FSH receptor, a real-time PCR for allelic discrimination was carried out using StepOnePlus™ Real-Time PCR System (Applied Biosystems™. Ref: 4376600). Non-parametic tests were used to study the differences between the groups. They were performed with the software R Statistical Software, version 4.0.3. Main results and the role of chance The results of ovarian stimulation in the luteal phase were better compared to the conventional follicular phase. Statistically significant differences (p In addition, better results were obtained in the luteal phase in patients who have been stimulated with the type of gonadotropin that already had better performance in the follicular phase for its genotype, that is, highly purified urinary FSH in SS patients and recombinant FSH in SN patients, compared to other types of gonadotropin (p We also observed that stimulation in the luteal phase lasts longer and consume more gonadotropins than in the follicular phase. This is especially notable in the case of patients with SS genotype, who required slightly higher consumption of gonadotropins compared to the other genotypes in the luteal phase, as had previously been observed in the follicular phase for this genotype. Limitations, reasons for caution The retrospective study design and the sample size could be a limitation. Furthermore, we cannot determine whether the improvement in luteal phase performance is related to differences in the physiological environment between phases of the cycle or is caused by a possible activation of the ovary from the previous stimulation. Wider implications of the findings: All patients undergoing in-vitro fertilization seems to benefit from luteal phase ovarian stimulation, regardless of their genotype for FSHR. In addition, the pharmacogenetic recommendation when choosing the type of FSH for ovarian stimulation should be the same both in the follicular phase and in the luteal phase. Trial registration number Not applicable

Is embryo cryopreservation a cause of high birth weight and large for gestational age (LGA) in singletons resulting from vitrified-warmed embryo transfer?Retrospective cohort study evaluating 670 oocyte recipients who underwent fresh (367 cycles) or vitrified-warmed embryo transfer (303 cycles) at Instituto Bernabeu between July 2017 and March 2019. All single blastocyst transfers carried out in an artificial cycle that resulted in a singleton live birth were included.Maternal age (42.21 ± 4.45; 42.79 ± 3.83; P = 0.519), body mass index (23.34 ± 3.69; 23.80 ± 3.78; P = 0.075), gestational age (38.96 ± 1.97; 38.77 ± 2.15; P = 0.207), maternal smoking (10.8%; 13.0%; P = 0.475), gestational diabetes (4.9%; 4.3% P = 0.854), preeclampsia (2.7%; 5.6%; P = 0.074), hypertensive disorders (3.3%; 2.3%; P = 0.494), maternal parity (multiparous 18.5%; 14.5%; P = 0.177) and liveborn gender (female 44.5%; 48.8%; P = 0.276) were not significantly different between fresh or vitrified-warmed groups. Endometrial thickness was significantly higher in the fresh versus vitrified-warmed group (8.83 ± 1.73 versus 8.57 ± 1.59; P = 0.035, respectively). Oocyte donor height was similar between the fresh versus vitrified-warmed group (163.22 ± 5.88 versus 164.27 ± 6.66 cm; P = 0.057, respectively). Mean birth weight was not significantly different (3239.21 ± 550.43; 3224.56 ± 570.83; adjusted P = 0.058). No differences were observed in macrosomia (7.1%; 6.3%; adjusted OR 0.857, 95% CI 0.314 to 2.340, P = 0.764), LGA (6.0%; 6.7%; adjusted OR 0.450, 95% CI 0.176 to 1.149, P = 0.095), pre-term birth (10.9%; 9.0% adjusted P = 0.997), very pre-term birth (0.8%; 1.3%; adjusted P = 1.000), extremely pre-term birth (0%; 1.0%; adjusted P = 0.998); underweight (10.0%; 7.0%; adjusted P = 0.050); very low weight (0.6; 1.1%; adjusted P = 1.000) and small for gestational age (1.9%; 0.7%; adjusted P = 0.974) between fresh or vitrified-warmed groups.This study eliminates potential confounders that might influence fetal growth and demonstrates that embryo vitrification and warming procedures do not affect birth weight.

Study question Does the use of pessaries of 400 mg of micronized progesterone provide comparable results as pessaries of 200 mg x2, in terms of progesterone levels? Summary answer The administration of pessaries of Cyclogest® 400 mg reduces the probability of presenting suboptimal level of progesterone on the day of the embryo transfer. What is known already The endometrial preparation for frozen embryo transfer (FET) in Artificial Cycle (AC) with vaginally-administered progesterone, is one of the most common IVF procedures nowadays. Now, it has been shown that suboptimal progesterone levels on the day of the embryo transfer compromise the results of FET treatments. Recently, a new preparation of 400 mg vaginal pessaries has been introduced in the market of European countries. Efficacy of this new preparation has been studied in “fresh” IVF cycles but we lack the comparative studies in AC making it necessary to further investigate this area. Study design, size, duration Non-inferiority retrospective case-control trial based on 347 embryo transfer treatments with endometrial preparation in AC carried out at Instituto Bernabeu between January 2019 and July 2020. 153 patients received 1 pessary of 400 mg every 12 hours (group A) and 194 received 2 pessaries of 200 mg every 12 hours (group B). Sampled size calculation resulted in 182 patients required to detect a minimum difference of 2 ng/ml so sample was powered for the purpose. Participants/materials, setting, methods Patients receiving embryos in AC preparation were included. All embryo transfers were performed at blastocyst stage after 5 days of progesterone administration. Progesterone levels were assessed the day of the embryo transfer by an electrochemiluminescence immunoassay.Primary outcome was the incidence of suboptimal progesterone levels according with the cutoff value stablished in the literature at 8.8 ng/mL. Secondary outcomes were pregnancy rates (PR), clinical pregnancy rates (CPR), ongoing pregnancy rates (OPR) and miscarriage rates (MR). Main results and the role of chance Incidence of suboptimal levels of progesterone was significantly lower in the group of 400 mg (9,8% in Group A vs 19,7% in the Group B, p = 0.011). Given that there was an imbalance between groups in the body weight (66.9 +/- 14 vs. 61.9 +/- 13.165 kg, p Limitations, reasons for caution The inherent limitations of a retrospective analysis. The study was not powered to detect differences in clinical outcomes. Therefore, results other than progesterone levels should be interpreted with caution. Wider implications of the findings: A single pessary of 400 mg minimizes the necessity of additional medication (usually subcutaneous progesterone). Presentation of 400 mg is superior to 2x200 providing adequate progesterone levels and patient comfort. Dose finding and pharmacokinetics studies of the vaginal administration will be necessary for the future to optimize FET under AC. Trial registration number NCT04722471

Study question Are there differences in the clinical outcomes of mosaic embryos depending on the female age? Summary answer Clinical outcomes of mosaic embryo transfers are similar regardless female age. What is known already Chromosomal abnormalities are common in embryos analyzed in preimplantation genetic testing for aneuploidy (PGT-A) cycles. Mosaicism (the presence of two or more chromosomally distinct cell lines) is a usual event in embryos derived from IVF cycles. Several studies show that mosaic embryos have reduced potential to reach term, compared to euploid embryos. The factors affecting the implantation potential and development of mosaic embryos are controversial. Recently, Victor et al. (2019) argued that mosaic blastocysts generated at younger ages show better outcomes compared to older ages. The aim of this study was to test this hypothesis in our centre. Study design, size, duration A total of 136 mosaic embryos from patients undergoing PGT-A cycles from May 2014 to October 2020 were retrospectively analyzed in this study. The blastocyst trophoectoderm biopsies of day 5 and 6 were analysed by aCGH (n = 47, 30.1%) and NGS (n = 109, 69.9%). An embryo was considered mosaic when the percentage of aneuploid cells were 25–50% in aCGH and 20–50% in NGS. Only single embryo transfer cycles were included in the analysis. Participants/materials, setting, methods Embryo analysis were performed using Agilent SurePrint G3 8x60K CGH microarrays or Veriseq NGS (Illumina), with previous whole genome amplification. We evaluated if clinical results of mosaic embryos transfers in IVF cycles were correlated with female age. The main outcome measures were β-hCG, implantation rate and ongoing pregnancy rate. β-hCG was measured in blood 14 days after the embryo transfer and was considered positive when it was >2 mUI/ml.The statistical analysis was performed with SPSSv20.0. Main results and the role of chance A total of 136 mosaic embryos were included in this study. Overall, we evaluated factors affecting embryo mosaicism implantation potential. Neither the percentage of mosaicism nor the segmental mosaicism were related to mosaic embryo implantation, pregnancy and ongoing pregnancy rates. To evaluate the impact of female age in clinical outcomes, we established two different groups depending on whether mosaic blastocysts were generated from oocytes retrieved at young maternal ages (≤35 years; n = 62) or at older ages (>35years; n = 74). No differences were found between groups. Nonetheless, to reduce bias, embryo quality, percentage of mosaicism, segmental mosaicism and whether the transferred embryo was frozen or fresh were included as confounding factors. The rate of positive β-hCG was similar between groups: 45.2% in ≤ 35y group vs 54.1% in > 35y (p = 0.476). The implantation rate was also similar: 30.6% vs 39.2%% (p = 0.855), respectively. Furthermore, the ongoing pregnancy rate was higher in the >35y group (35.1%), compared to the ≤35y group (19.4%) without reaching statistically significant differences (p = 0.245). Limitations, reasons for caution The sample size is a limitation. aCGH test and a different definition for mosaic embryo in terms of percentage of abnormal cells was employed in this study compared to Victor et. al. (2019) study. Larger prospective studies should evaluate the impact of maternal age in the outcome of mosaic embryos. Wider implications of the findings: Our results challenge that female age is associated with clinical outcomes after the transfer of mosaic embryos. Comparable results were obtained in young and older women. Therefore, in the absence of euploid embryos, mosaic embryos might be considered for transfer and similar outcomes are expected regardless of the maternal age. Trial registration number Not applicable

Study question Could cryptic subtelomeric traslocations in early recurrent miscarriage patients be diagnosed by preimplantation genetic testing? Summary answer PGT is a powerful tool to detect subtelomeric cryptic traslocations identifying the cause of early recurrent miscarriage and allowing subsequent genetic counselling. What is known already: Chromosome translocations are frequently associated with birth defects, spontaneous early pregnancy losses and infertility. However, submicroscopic traslocations (so-called cryptic traslocations) are too small to be detected by conventional karyotyping.. Due to balanced status, high resolution molecular techniques as arrayCGH are not able to detect it. Thus, cryptic traslocations detection is challenging. PGT is able to detect CNVs at higher resolution than routine karyotyping. Therefore, the recurrent diagnosis of CNV at embryo level could suggest a subchromosomal parental traslocation. The aim of this study is to investigate the feasibility of using PGT as an indicator of parental balanced cryptic traslocations. Study design, size, duration We included three couples who underwent PGT for unexplained repeated pregnancy loss (RPL) in our clinic from February 2020 to November 2020. Common established causes of RPL (uterine anomalies, antiphospholipid syndrome, immunological, hormonal and metabolic disorders) were previously rouled-out. Even couple karyotypes were normal. Twenty-three embryos from those couples were biopsied at blastocyst and analysed for CNVs detection using low coverage whole genome NGS. Participants/materials, setting, methods PGT by NGS was performed by Veriseq-NGS (Illumina), with previous whole genome amplification. Fluorescence in situ hybridization (FISH) using parental blood samples were performed to validate the origin of subchromosomal number variation. Commercially available subtelomeric specific probes were selected according to the CNV identified and the procedures were performed according to the manufacturer’s protocols. Main results and the role of chance Overall, CNVs of terminal duplication and deletion that imply unbalanced traslocation derivatives were detected in the 43.5% of biopsied embryos. For couple 1, 4 out of 5 embryos (80%) carried deletion of telomeric region on chromosomes 5 and 21. Three out of 6 biopsed embyos (50%) were diagnosed with subchromosomal copy variants at telomeric region on chromosomes 6 and 16 for couple 2. In the case of couple 3, three out of 12 embryos (25%) were carriers of CNV at subtelomeric region on chromosomes 2 and 6. The size of CNVs detected ranges from 8Mb to 20Mb. Accurate diagnosis with the parental study was made by FISH. The combination of probes to detect the structural chromosome alteration were: Tel5qter-LSI21q, Tel6pter-CEP16 and Tel6pter-CEP6 for each couple respectively. The FISH studies reveal that CNVs were inherited from one parent carrying the balanced cryptic traslocation. Ultimately, the abnormal karyotype from the carrier parent were 46,XY,t(5;21)(q33.2;q21.2) for couple 1, 46,XY,t(6;16)(p22.3;q22.1) for couple 2 and 46,XY,t(2;6)(p25.1;p24.2) for couple 3. Finally, each couple performed a cryotransfer of a single normal balanced embryo. Two pregnancies are ongoing. Limitations, reasons for caution The main limitation of this approach is the NGS- PGT resolution. CNVs smaller than 5Mb could not be detected. Wider implications of the findings: This study shows the value of PGT for unexplained RPL, followed by parental FISH to better characterize CNVs and identify couples in whom one partner carries a cryptic translocation. Accurate diagnosis of parental chromosome translocation can achieve with FISH only, but FISH would not be performed unless PGT showed CNVs. Trial registration number Not applicable

Study question Is it possible to predict the likelihood of an IVF embryo being aneuploid and/or mosaic using a machine learning algorithm? Summary answer There are paternal, maternal, embryonic and IVF-cycle factors that are associated with embryonic chromosomal status that can be used as predictors in machine learning models. What is known already The factors associated with embryonic aneuploidy have been extensively studied. Mostly maternal age and to a lesser extent male factor and ovarian stimulation have been related to the occurrence of chromosomal alterations in the embryo. On the other hand, the main factors that may increase the incidence of embryo mosaicism have not yet been established. The models obtained using classical statistical methods to predict embryonic aneuploidy and mosaicism are not of high reliability. As an alternative to traditional methods, different machine and deep learning algorithms are being used to generate predictive models in different areas of medicine, including human reproduction. Study design, size, duration The study design is observational and retrospective. A total of 4654 embryos from 1558 PGT-A cycles were included (January-2017 to December-2020). The trophoectoderm biopsies on D5, D6 or D7 blastocysts were analysed by NGS. Embryos with ≤25% aneuploid cells were considered euploid, between 25-50% were classified as mosaic and aneuploid with >50%. The variables of the PGT-A were recorded in a database from which predictive models of embryonic aneuploidy and mosaicism were developed. Participants/materials, setting, methods The main indications for PGT-A were advanced maternal age, abnormal sperm FISH and recurrent miscarriage or implantation failure. Embryo analysis were performed using Veriseq-NGS (Illumina). The software used to carry out all the analysis was R (RStudio). The library used to implement the different algorithms was caret. In the machine learning models, 22 predictor variables were introduced, which can be classified into 4 categories: maternal, paternal, embryonic and those specific to the IVF cycle. Main results and the role of chance The different couple, embryo and stimulation cycle variables were recorded in a database (22 predictor variables). Two different predictive models were performed, one for aneuploidy and the other for mosaicism. The predictor variable was of multi-class type since it included the segmental and whole chromosome alteration categories. The dataframe were first preprocessed and the different classes to be predicted were balanced. A 80% of the data were used for training the model and 20% were reserved for further testing. The classification algorithms applied include multinomial regression, neural networks, support vector machines, neighborhood-based methods, classification trees, gradient boosting, ensemble methods, Bayesian and discriminant analysis-based methods. The algorithms were optimized by minimizing the Log_Loss that measures accuracy but penalizing misclassifications. The best predictive models were achieved with the XG-Boost and random forest algorithms. The AUC of the predictive model for aneuploidy was 80.8% (Log_Loss 1.028) and for mosaicism 84.1% (Log_Loss: 0.929). The best predictor variables of the models were maternal age, embryo quality, day of biopsy and whether or not the couple had a history of pregnancies with chromosomopathies. The male factor only played a relevant role in the mosaicism model but not in the aneuploidy model. Limitations, reasons for caution Although the predictive models obtained can be very useful to know the probabilities of achieving euploid embryos in an IVF cycle, increasing the sample size and including additional variables could improve the models and thus increase their predictive capacity. Wider implications of the findings Machine learning can be a very useful tool in reproductive medicine since it can allow the determination of factors associated with embryonic aneuploidies and mosaicism in order to establish a predictive model for both. To identify couples at risk of embryo aneuploidy/mosaicism could benefit them of the use of PGT-A. Trial registration number Not Applicable

Study question Does a previous Caesarean section affect uterine vascularisation the day of embryo transfer? Summary answer 3D vascularisation parameters show less uterine irrigation in patients with previous Caesarean section What is known already A recent retrospective cohort study demonstrates that previous Caesarean section impairs live birth rates after assisted reproductive treatment (ART) compared to a previous vaginal delivery. Furthermore, it has been hypothesized about the mechanisms by which post-cesarean section niche may diminish clinical pregnancy rates. One of the hypothetical process mentioned has been a distorted contractility of the uterus caused by fibrosis, which can influence in the vascularisation of the endometrium. Study design, size, duration We retrospectively studied the uterine contractility and 3D vascularisation parameters in women who had an embryo transfer at the Instituto Bernabeu of Alicante, between 2018 and 2020 with one recurrent implantation failure (at least two good quality blastocysts transferred from egg donation treatment). Participants/materials, setting, methods Patients with large myomas (more than 4 cm), adenomyosis or polyp were excluded. In total, 196 patients were assessed on the day of embryo transfer which 12 patients had a previous caesarean section. Uterine contractility was analyzed using 4D ultrasound after 6 minutes of video recording. Vascularisation index and vascularisation flow index were assessed after the endometrial volume definition. Main results and the role of chance Baseline characteristics of both groups were comparable. 3D vascularization parameters were significantly lower in women with a previous caesarean section. Vascularization Index (VI) reached 0,8% in caesarean section group (CS group) versus 2,3% (p = 0,038) and vascularization flow index (VFI) was 0,2 in CS group versus 0,8 (p = 0,038) Despite uterine peristalsis showed less contractility in those patients with previous caesarean section (0,8 contractions per minute versus 1,1 contractions per minute), non-statistical differences were demonstrated (p = 0,154) Limitations, reasons for caution This study is limited by its retrospective design and the low number of cases. Wider implications of the findings: The lower 3D vascularisation indexes support a post-Caesarean section vascular-related impaired perfusion as a hypothetical mechanism. Its correlation with a possible impairment in the embryo implantation after fertility treatments warrants further studies. Trial registration number Not applicable

Study question What is the effect of artificial laser-assisted collapse before vitrification on pregnancy and implantation rates after transfer of vitrified-warmed blastocysts? Summary answer The artificial shrinkage by laser-induced collapse before vitrification significantly increased the implantation and clinical pregnancy rates after single thawed embryo transfer. What is known already Freeze all, cycle segmentation and, in general, single embryo transfer (SET) strategies (for example trophectoderm biopsy-based aneuploidy testing) have targeted blastocysts vitrification as the best option for reproductive practice worldwide. Artificial shrinkage seems to be a pre-vitrification parameter associated with an increased embryo survival after warming and implantation rate. However, the available medical evidence shows controversial results with only a limited number of prospective studies assessing the subject. Study design, size, duration This prospective cohort study evaluated 394 women who underwent a frozen blastocyst transfer at Instituto Bernabeu between July and December 2020. All patients were prepared with substitutive cycle and received single blastocyst embryo transfers. Participants/materials, setting, methods Before embryo vitrification on day 5 of development, some expanded and/or early hatching blastocysts (A/B ASEBIR categories) were artificial laser-assisted collapsed. (n = 83, study group). 311 embryos of the same quality and day of development were not collapsed (control group). We compared the embryo survival rate, clinical, implantation and miscarriage rates between groups. The statistical analysis was performed using SPSS (version 20.0). Main results and the role of chance The two groups were comparable in terms of maternal age (39.79 ± 3.83, control group; 40.21 ± 4.45, study group; p = 0.341). Embryo survival rate resulted in 100% in both groups. Regarding clinical outcomes, collapsed blastocysts significantly increased the positive pregnancy test and the clinical pregnancy and implantation rate compared to the control group, respectively (positive test: 69,9% vs 43,4%, p = 0.000018, odds ratio (OR)= 3.02 [95% CI 1.80–5.08]; clinical pregnancy and implantation: 56,6% vs 35,4%, p = 0.000041, OR = 2.39 [95% CI 1.46–3.90]). The miscarriage rate was not affected by the blastocyst collapse effect (23,6% in the control group vs 27,6% in the study group, p = 0.593, OR = 1.23 [95% CI 0.57–2.68]). Limitations, reasons for caution This is a non-randomized controlled study. Additional RCTs are warranted to corroborate our findings. Wider implications of the findings: Considering the large number of blastocyst vitrification cycles that are carried out worldwide, artificial laser-assisted collapse before vitrification has the potential to increase the clinical results in benefit of many patients. Trial registration number Not applicable

Study question Is it possible to identify a genetic cause of familial premature ovarian failure (POF) with whole-exome sequencing (WES)? Summary answer Whole-exome sequencing is the most efficient strategy to identify probably pathogenic mutations in different genes in pathologies of polygenic etiology such as premature ovarian failure. What is known already Premature ovarian failure is the loss of ovarian function before the age of 40, and it is a common cause of infertility in women. This pathology has a heterogeneous etiology. Some chromosomal and genetic alterations have been described, and could explain approximately 20% of cases. However, in most patients the origin remains unknown. Recent studies with next-generation sequencing (NGS) have identified new variants in candidate genes related with premature ovarian insufficiency (POI) or premature ovarian failure (POF). These genes are not only involved in processes such as folliculogenesis, but also with DNA damage repair, homologous recombination, and meiosis. Study design, size, duration Fourteen women, from 7 families, affected by idiopathic POF were included in the study from October 2019 to September 2020. Seven POF patients were recruited when they came to our clinic to undergo assisted reproductive treatment. In the anamnesis, it was found that they had relatives with a diagnosis of POF, who were also recruited for the study. The inclusion criteria were amenorrhea before 38 years old and analytical and ultrasound signs of ovarian failure. Participants/materials, setting, methods WES was performed using TrusightOne (Illumina®). Sequenced data were aligned through BWA tool and GATK algorithm was used for SNVs/InDel identification. VCF files were annotated using Variant Interpreter software. Only the variants shared by each family were extracted for analysis and these criteria were followed: (1) Exonic/splicing variants in genes related with POF or involved in biological ovarian functions (2) Variants with minor allele frequency (MAF) ≤0.05 and (3) having potentially moderate/strong functional effects. Main results and the role of chance Seventy-nine variants possibly related with the POF phenotype were identified in the seven families. All these variants had a minor allele frequency (MAF) ≤0.05 in the gnomAD database and 1000 genomes project. Among these candidate variants, two were nonsense, six splice region, one frameshift, two inframe deletion and 68 missense. Thirty-two of the missense variants were predicted to have deleterious effects by minimum two of the four in silico algorithms used (SIFT, PolyPhen–2, MutationTaster and PROVEAN). All variants were heterozygous, and all the families carried three or more candidate variants. Altogether, 43 probably damaging genetic variants were identified in 39 genes expressed in the ovary and related with POF/POI or linked to ovarian physiology. We have described genes that have never been associated to POF pathology, however they may be involved in key biological processes for ovarian function. Moreover, some of these genes were found in two families, for example DDX11, VWF, PIWIL3 and HSD3B1. DDX11 may function at the interface of replication-coupled DNA repair and sister chromatid cohesion. VWF gene is suggested to be associated with follicular atresia in previous studies. PIWIL3 functions in development and maintenance of germline stem cells, and HSD3B1 is implicated in ovarian steroidogenesis. Limitations, reasons for caution Whole-exome sequencing has some limitations: does not cover noncoding regions of the genome, it also cannot detect large rearrangements, copy-number variants (large deletions/duplications), mosaic mutations, mutations in repetitive or high GC rich regions and mutations in genes with corresponding pseudogenes or other highly homologous sequences. Wider implications of the findings: WES has previously shown to be an efficient tool to identify genes as cause of POF, and has demonstrated the polygenic etiology. Although some studies have focused on it, and many genes are identified, this study proposes new candidate genes and variants, having potentially moderate/strong functional effects, associated with POF. Trial registration number Not applicable

Study question Could vaginal and endometrial microbiome by sequencing 16S rRNA be comparable to classic diagnostic methods or immunohistochemistry CD138 for diagnosis of chronic endometritis? Summary answer A characteristic endometrial and vaginal microbiome is present in patients with chronic endometritis. An abnormal vaginal microbiome correlates with the presence of chronic endometritis. What is known already Chronic endometritis is a disease characterized by persistent inflammation of the endometrial lining. Currently, histopathological evaluation by immunohistochemistry CD138 marker is most common diagnostic method for CE. Microbiome analysis based on subunit 16S rRNA sequencing is a fast tool that can enable the identification of pathogenic microorganisms associated with CE. The main bacteria at vaginal and endometrial level belong to genus Lactobacillus, producers of lactic acid that allows maintaining acidic pH of vagina and acts as barrier against pathogens. Investigations on the effect of an abnormal endometrial and vaginal microbiome could improve assisted reproductive technologies. Study design, size, duration This is a observational pilot study (60 patients and 120 samples). The study population consists of patients attending to our fertility clinic for frozen euploid embryo transfer (FET) from May 2017 to May 2019. Preimplantation Genetic Testing of aneuploidy (PGT-A) was performed at blastocyst stage using Veriseq (Illumina). The inclusion criteria to be meet by patients were: age between 18 and 50 years, own or donated oocytes and use of ICSI. Participants/materials, setting, methods Cohort study with sixty patients undergoing assisted reproductive treatment (TRA) with their own or donated gametes and PGT-A Vaginal and endometrial samples were taken in the cycle prior to embryo transfer. The vaginal and endometrial microbiome was analyzed by mass sequencing of the V3V4 region of 16S rRNA. Bioinformatics analysis was performed using QIIME2 and MicrobiomeAnalyst packages. Alpha, beta diversity and taxonomic characterization were compared with positive and negative CD138 groups for chronic endometritis (CE). Main results and the role of chance Different bacterial communities were detected when vaginal and endometrial samples were analyzed in patients with and without endometritis diagnosed with CD138 immunohistochemistry. In patients with endometritis, a higher alpha diversity index tendency was found in vaginal samples (p = 0.15 for the Shannon index) and significant differences in endometrial samples (p = 0.01 for the Shannon index). In the beta diversity analysis, no significant differences were observed between the groups established as per the diagnosis of endometritis. Vaginal and endometrial samples from women with endometritis showed a microbiome pattern not dominated by Lactobacillus spp. Relative abundance analysis identified the genera Ralstonia and Gardnerella in endometrial sample, and the genera Streptoccoccus and Ureaplasma in vaginal sample of patients diagnosed with CD138 for endometritis. Comparing endometrial and vaginal samples CD138 positive diagnosed for endometritis, alpha diversity (p = 0.06 for the Shannon index and p = 0.08 for the Simpson index) and beta diversity (p Limitations, reasons for caution The main limitation of this study is the small sample size. Larger studies including a higher number of samples are needed to confirm the different microbiome pattern observed at the vaginal and endometrial levels in correlation with chronic endometritis. The microbiome pattern has not been analyzed after treatment of CE. Wider implications of the findings Our findings suggest the existence of a characteristic vaginal and endometrial microbiota in patients with chronic endometritis. Different genera and species were identified in patients with and without endometritis depending on whether the sample was endometrial or vaginal. An abnormal vaginal microbiome appears to be strongly correlated with chronic endometritis. Trial registration number Not Applicable

Study question For donor oocyte recipients, are clinical outcomes superior for fresh versus frozen euploid embryos? Summary answer Among donor oocyte recipients receiving euploid embryos, fresh embryos are associated with superior clinical outcomes when compared with frozen embryos. What is known already A recent large retrospective cohort national registry study reported that among donor oocyte recipients, fresh embryos were associated with better clinical outcomes when compared with frozen embryos. This finding contrast with data from autologous oocytes. Since embryo quality at embryo transfer (ET) may introduce a significant confounder, the additional analysis of recipients receiving only euploid embryos may add important information on the subject. Study design, size, duration Retrospective cohort analysis of PGT-A IVF-cycles of women using donor oocytes resulting in fresh blastocyst ET compared to the first frozen blastocyst ET from freeze-all cycles between 2014 and 2020 at Instituto Bernabeu, Alicante, Spain. A total of 349 donor oocyte cycles were analyzed, in which 211 were fresh and 138 were frozen ETs. Thawed oocytes were not excluded. Participants/materials, setting, methods Clinical pregnancy (gestational sac plus embryo heart beating at 6–7 weeks), was the primary outcome measure. Secondary outcomes included pregnancy and early pregnancy loss rate. aCGH platform tested the embryos transferred in fresh whereas either aCGH or NGS platforms were used for embryos submitted to elective frozen cycles. Vitrification was used as cryopreservation technique. Fresh transfers were performed in artificial cycles. Different types of endometrial preparations were used for FET in the study. Main results and the role of chance Recipients in the fresh group were significantly younger and had more embryos transferred compared to the frozen group (41.3 vs 42.5 and 1.2 vs 1.1, respectively). More clinical pregnancies were observed in the fresh compared to the frozen group (108/211 versus 54/138, respectively, odds ratio (ODR) 1.63 [95% CI 1.05–2.52]; p = 0.02). Pregnancy rates were also higher in the fresh compared to the frozen group (128/211 versus 63/138, respectively, odds ratio (ODR) 1.83 [95% CI 1.18–2.83]; p = 0.005). Early pregnancy losses were similar in both groups (p = 0.2). Limitations, reasons for caution Implantation failure and abnormal male tests were the most frequent indications for PGT-A. Because of the observational nature of the results in this limited sample size, a cause–effect relationship should not be assumed; evidence from larger well-designed randomized control trials is still required before clinical advice can be suggested. Wider implications of the findings: When PGT-A analysis is deemed to be necessary in oocyte recipients, cryopreservation may have an adverse impact on IVF outcomes. Future studies exploring ET in natural vs artificial cycles are warranted to further isolate the impact of vitrification and the uterine environment on IVF outcomes. Trial registration number Not applicable

Study question Can we rescue treatments with low progesterone (PG) levels the day of frozen embryo transfer (FET) by adding subcutaneous progesterone? Summary answer After receiving additional supplementation with subcutaneous progesterone, women with low serum progesterone on cryotransfer day, have similar ongoing pregnancy rates as women with normal levels. What is known already Micronized vaginal progesterone fails to achieve optimal serum levels in up to 30% of patients receiving frozen embryos under artificial cycles (AC) despite the administration of 400 mg twice daily. Cancelling the thawing process and restarting a new treatment is a very disappointing option for patients and doctors. An alternative strategy is to administrate additional progesterone subcutaneously. The efficacy of the additional administration of subcutaneous progesterone as a “rescue” strategy in terms of clinical outcomes remains to be validated. Study design, size, duration We included 356 FET performed at Instituto Bernabeu between January 2019 - August 2020 in a retrospective case-control study. Groups were established according to PG levels on the day of the embryo transfer. The Control Group included: patients with optimal progesterone levels (≥8.8 ng ml); while the Rescue Group included those with suboptimal progesterone levels ( Participants/materials, setting, methods All patients performed frozen embryo transfer after artificial endometrial preparation. All embryo transfers were performed at blastocyst stage after 5 days of progesterone administration. Progesterone levels were assessed the day of the embryo transfer by an electrochemiluminescence immunoassay. Samples were obtained 2–5 hours after the last vaginal progesterone administration. Primary outcome was Ongoing Pregnancy Rates (OPR). Secondary outcomes were pregnancy rates (PR), miscarriage rates (MR) and biochemical miscarriage (BM). Main results and the role of chance 301 patients were included in the Control Group and 55 in the Rescue Group. No significant differences were found between both groups. OPR rate was 34.7% for patients in the control group versus 26.4% in the rescue group (p = 0.240) PR was 52.5% for patients with optimal PG levels vs 54.5% when PG levels were below 8.8 ng/mL. Both BM and MR tend to be higher in women who had low serum PG: BM (21.4% vs 15.5%) and MR (28.6% vs 18.1%), without reaching significant statistical difference. In addition, we analyzed data from a sub-group of patients who received extra subcutaneous progesterone (based on cliniciańs decision), despite having normal serum PG levels. No differences in clinical outcomes between these groups were observed either. OPR was 29%, vs 35.4% (p = 0.241), PR was 51.8% vs 53.7%; BM was 16.7% vs 16.3% and MR was 26.9% vs 17.1% between women who received an extra subcutaneous PG dose versus women who did not, respectively. Weight and BMI distribution were homogeneous across groups. A discreet difference was observed in age distribution (control group mean age 41.6 years vs. 39.7 years in the rescue group). Limitations, reasons for caution The retrospective collection of data and a limited sample size constitutes the main limitations of the study. Significant statistical differences were not found between groups but still differences might be clinically relevant. Larger studies are needed to reach robust conclusions on the strategy. Wider implications of the findings: In AC cycles, when supplemented with additional subcutaneous progesterone, women showing low serum progesterone on cryotransfer day may expect similar clinical outcomes as women with normal levels. Pending on confirmatory studies, this strategy could consider as an alternative to cycle cancellation. Trial registration number Not applicable

Uterine microbiota may be involved in reproductive health and disease. This study aims to describe and compare the vaginal and endometrial microbiome patterns between women who became pregnant and women who did not after in vitro fertilization. We also compared the vaginal and endometrial microbiome patterns between women with and without a history of repeated implantation failures (RIF). This pilot prospective cohort study included 48 women presenting to the fertility clinic for IVF from May 2017 to May 2019. Women who achieved clinical pregnancy presented a greater relative abundance of Lactobacillus spp. in their vaginal samples than those who did not (97.69% versus 94.63%, p = 0.027. The alpha and beta diversity of vaginal and endometrial samples were not statistically different between pregnant and non-pregnant women. The Faith alpha diversity index in vaginal samples was lower in women with RIF than those without RIF (p = 0.027). The alpha diversity of the endometrial microbiome was significantly higher in women without RIF (p = 0.021). There were no significant differences in the vaginal and endometrial microbiomes between pregnant and non-pregnant women. The relative abundance of the genera in women with RIF was different from those without RIF. Statistically significant differences in the endometrial microbiome were found between women with and without RIF.

The aim of our study was to investigate the effect of maternal and embryo MTHFR C677T and A1298C polymorphisms on embryo aneuploidies and mosaicism and the correlation between these genetic variant...

The evaluation of sperm DNA fragmentation has been postulated as a predictive molecular parameter of the semen fertilising potential, as well as the ability to give rise to a healthy embryo and an ongoing pregnancy. However, there are controversial results due to oocyte quality, the use of different measurement techniques and interpretation criteria. Our objective is to investigate if sperm DNA fragmentation on the day of fertilisation influences

There is a high incidence of chromosome abnormalities in human embryos that leads to a failed IVF cycle. Different studies have shown that maternal age is the determining factor in the appearance of chromosomal alterations in the embryo. However, the possible influence of ovarian stimulation on oocyte and embryo aneuploidies and mosaicism is controversial. A retrospective study was carried out in which 835 embryos from 280 couples undergoing reproductive treatment using their oocytes were chromosomally analyzed. A binary logistic regression analysis was performed to evaluate the relationship between different parameters characterizing controlled ovarian stimulation (COS) and the rate of aneuploidy and embryonic mosaicism. The embryo aneuploidy rate showed no association with the use of oral contraceptives, type, total and daily doses of gonadotropins, stimulation protocol type, and drugs used for ovulation trigger (p > 0.05). In contrast, the duration of the ovarian stimulation treatment was correlated with the aneuploidy rate: patients requiring more days of stimulation presented a lower rate of aneuploid embryos (p = 0.015). None of the variables studied showed any association with the rate of embryo mosaicism. However, the duration of COS showed association with the appearance of aneuploidy, suggesting that faster recruitment could be deleterious for those reassuming meiosis, yielding more abnormal karyotype. Abbreviations: IVF: in vitro fertilization; COS: controlled ovarian stimulation; PGT-A: preimplantation genetic test for aneuploidy; hCG: human chorionic gonadotropin; GnRH: gonadotropin-releasing hormone; LH: luteinizing hormone; FSH: follicle-stimulating hormone; NGS: next-generation sequencing; a-CGH: comparative genomic hybridization; TUNEL: Terminal transferase dUTP Nick End Labeling; FISH: fluorescent in situ hybridization

Objective: To compare the endometrial and vaginal microbiome of women with and without chronic endometritis. Study design: A cohort study with 60 patients undergoing assisted reproductive treatment with their own or donated gametes was undertaken. Vaginal and endometrial samples were taken in the cycle prior to embryo transfer. The endometrial and vaginal microbiome was analysed by mass sequencing of the V3V4 region of 16S rRNA gene. Bioinformatics analysis was performed using QIIME2 and MicrobiomeAnalyst packages. Alpha diversity, beta diversity and taxonomic characterization were compared between samples that tested positive and negative for chronic endometritis on CD138 immunohistochemistry. Results: Different bacterial communities were detected when vaginal and endometrial samples were analysed in patients with and without endometritis diagnosed using CD138 immunohistochemistry. In patients with endometritis, a higher alpha-diversity index was found in vaginal samples (p = 0.15 for the Shannon index) and significant differences were found in endometrial samples (p = 0.01 for the Shannon index). In the beta-diversity analysis, no significant differences were observed between the groups with and without endometritis. Vaginal and endometrial samples from women with endometritis showed a microbiome pattern that was not dominated by Lactobacillus spp. Relative abundance analysis identified Ralstonia and Gardnerella spp. in endometrial samples, and Streptoccoccus and Ureaplasma spp. in vaginal samples of patients diagnosed with chronic endometritis on CD138 immunohistochemistry. When comparing endometrial and vaginal samples diagnosed with endometritis on CD138 immunohistochemistry, both alpha diversity (p = 0.06 for the Shannon index and p = 0.08 for the Simpson index) and beta diversity (p < 0.001) showed significant differences. Lactobacillus spp. (p = 3.76E-4), Ralstonia spp. (p = 8.19E-4), Delftia spp. (p = 0.004) and Anaerobacillus spp. (p = 0.004) were identified in these sample groups. Conclusion: These results demonstrate the existence of a characteristic vaginal and endometrial micro biota in patients with chronic endometritis. Different genera and species were identified in patients with and without chronic endometritis depending on whether the sample was endometrial or vaginal. There is a clear relationship between changes in the vaginal microbiome and chronic endometritis. The micro biota is a continuum throughout the female reproductive tract, so study of the vaginal microbiota could be useful for the diagnosis of diseases of the upper reproductive tract, such as chronic endometritis. (c) 2021 Elsevier B.V. All rights reserved.

El crecimiento de los tratamientos con embriones congelados ha sido exponencial en los últimos años por lo que la elección de la correcta preparación endometrial es uno de los puntos críticos en los procesos de FIV. Dicha preparación puede realizarse mediante ciclo natural sin la administración de medicación alguna (con su variante «ciclo natural modificado») o con la administración secuencial de estrógenos y progestágenos «ciclo sustituido o artificial». Si bien no se han descrito diferencias entre ambas aproximaciones en términos de eficacia, cada uno presenta ventajas e inconvenientes, tanto para la paciente como para el equipo que la trata. El ciclo natural presentaría ventajas en cuanto a comodidad y coste mientras que el sustituido permitiría una mayor flexibilidad en la programación de la transferencia. En los próximos años la seguridad para la salud de la gestante y el RN será clave para dilucidar la superioridad de un protocolo u otro.

Background:The vaginal microbiome plays an important role in maintaining health, and there is evidence that microbial colonization of the upper genital tract can also influence successful embryo transfer. The aim of this study is to determine whether the vaginal and endometrial microbiome in people undergoing assisted reproduction techniques could affect the pregnancy rate.Results:Regarding the microbiome dynamics during the cycle, we observed a decrease in alpha diversity from the follicular to luteal phase in the control group, in contrast to a stable pattern in the repetitive implantation failure group. As for endometrial and vaginal microbiome, alpha diversity was higher in the endometrium (Shannon p = 0.0139, Simpson p = 0.046); differences were also observed in beta diversity (p = 0.001). Compared to the endometrium, the vagina showed a greater relative abundance of Lactobacillus spp. (83.17% vs 84.82%, p Streptococcus spp. (1.59% vs 7.74%, p = 0.014) and Ureaplasma spp. (0% vs. 0.89%, p = 0.006), and a lower abundance of Delftia spp. (0.95% vs 0%, p = 0.0003), Anaerobacillus spp. (1.59% vs 0%, p = 0.0004), and Ralstonia spp. (3.17% vs 0%, p = 0.0006). We also observed differences in both alpha diversity (Shannon p = 0.0206, Simpson p = 0.0206) and beta diversity between groups, along with differences for Ralstonia spp. (0.09% study group and 0.73% control, p = 0.0012). Finally, the relative abundance of Lactobacillus spp. differed between patients that did not versus did achieve pregnancy (91% vs 99%, p = 0.0445 visit 1, 94.63% vs. 97.69%, p = 0.0268 visit 2, 97.73% vs 99.74%, p = 0.0492 visit 3). The relative abundance of L.reuteri was also different between groups (0.39% vs 0.17%, p = 0.0397 visit 1, 0.15% vs 0.30%, p = 0.0491 visit 3).Conclusions:The vaginal and endometrial microbiome pattern correlates with the pregnancy rate, and it is different in patients who do versus do not have repetitive implantation failures. No significant differences in the composition of the microbiome were observed through the different visits. The lack of dynamism in the microbiome pattern of repetitive implantation failure patients might reflect an impaired adaptation to endometrial changes. A greater relative abundance of Lactobacillus spp. and L. reuteri is correlated with higher chances of pregnancy.*MC Díaz Martínez and A Bernabeu García share equal responsibility for authorship.

Research question Are discordances in non-invasive preimplantation genetic testing for aneuploidies (niPGT-A) results attributable to the technique used for chromosomal analysis? Design A prospective blinded study was performed (September 2018 to December 2019). In total 302 chromosomal analyses were performed: 92 trophectoderm PGT-A biopsies and their corresponding spent embryo culture medium (SCM) evaluated by two methods (n = 184), negative controls (n = 8), and trophectoderm and inner cell mass biopsies from trophectoderm-aneuploid embryos (n = 18). Trophectoderm analyses were carried out using Veriseq (Illumina), and SCM was analysed using Veriseq and NICS (Yikon). Results Genetic results were obtained for 96.8% of trophectoderm samples versus 92.4% for both SCM techniques. The mosaicism rate was higher for SCM regardless of the technique used: 30.4% for SCM-NICS and 28.3% for SCM-Veriseq versus 14.1% for trophectoderm biopsies (P = 0.013, P = 0.031, respectively). No significant differences in diagnostic concordance were seen between the two SCM techniques (74.6% for SCM-NICS versus 72.3% for SCM-Veriseq; P = 0.861). For embryos biopsied on day 6, these rates reached 92.0% and 86.5%, respectively. On reanalysing trophectoderm-aneuploid embryos, the discrepancies were shown to be due to maternal DNA contamination (55.6%; 5/9), embryo mosaicism (22.2%; 2/9) and low resolution in SCM-NICS (11.1%; 1/9) and in both SCM techniques (11.1%; 1/9). Conclusions This is the first study evaluating the consistency of different chromosomal analysis techniques for niPGT-A. In conclusion, the diagnostic concordance between PGT-A and niPGT-A seems independent of the technique used. Optimization of culture conditions and medium retrieval provides a potential target to improve the reliability of niPGT-A.

Recurrent pregnancy loss (RPL; defined as the loss of three or more consecutive pregnancies) and recurrent implantation failure (RIF; when implantation is not achieved after at least three cycles o...

The AR (androgen receptor) polymorphism is associated with POR risk. Furthermore, the use of androgens in POR remains controversial. Our data could clarify the effectiveness of androgen pretreatment. AR genotyping could help us to identify patients at risk for POR and POR patients that will be benefited of androgen pretreatment. OBJECTIVE The aim of this project was to investigate if the AR (androgen receptor) polymorphism could be used to identify patients at risk for POR and that will benefit from androgens pretreatment. STUDY DESIGN To evaluate the POR risk we performed a cohort study including 231 patients (54 POR and 177 control). Moreover, we included 88 IVF-cycles performed by 44 POR-patients to assess the effect on ovarian response. All patients performed two cycles: a standard ovarian stimulation and a second one with androgen preparation. We compare the results in pair from each. RESULTS POR showed the highest frequency of CAG repeats at 24 vs 22 in controls. Only 33% of POR have alleles with a repeat number below 23, compared with 50% of controls (p

We report the first case of OHSS following GnRH agonist trigger for final follicular maturation in random start ovarian stimulation for egg-donation cycles during inadvertent concomitant early pregnancy. As an additional note, the sustained activity exerted by the increasing endogenous hCG production seemed to be responsible for the suboptimal performance in terms of oocyte yield in the current case. OHSS can occur in random-start stimulations protocols even after the use of a GnRH agonist for triggering in case of concomitant unnoticed early pregnancy especially if stimulation is commenced in the periovulatory/luteal phase. The present case report introduces a note of extreme caution when proceeding with this protocol in an otherwise fertile population (egg-donors, elective or oncologic oocyte cryopreservation).

Resumen Objetivo Comprobar si hay diferencias en el volumen y la vascularizacion trofoblastica en edades tempranas del embarazo entre gestaciones espontaneas y las conseguidas mediante tecnicas de reproduccion asistida (TRA). Metodos Se realizo un estudio observacional prospectivo de embarazos unicos en la semana 9, mediante ecografia transvaginal con tridimension y power doppler. Los volumenes adquiridos fueron analizados utilizando el programa de imagen VOCAL –Virtual Organ Computer-Aided Analysis–, para evaluar el volumen de la placenta, el indice de vascularizacion, el indice de flujo y el indice de vascularizacion de flujo. Resultados De 59 gestantes incluidas en el estudio, 32 se habian sometido a tratamientos de esterilidad y 27 eran gestaciones espontaneas. En un analisis comparativo todos los factores a estudio mostraron diferencias estadisticamente significativas. Las medias de estos valores para el grupo de tecnicas de reproduccion asistida fueron significativamente menores. Conclusiones El estudio de la volumetria y la vascularizacion trofoblastica podria ser de utilidad para comprender y prevenir la afeccion placentaria mas habitual en las gestaciones conseguidas tras tecnicas de reproduccion asistida y que explicarian algunos resultados perinatales adversos en este tipo de gestaciones.

Objective Monozygotic twinning incidence following preimplantation genetic testing in embryos at cleavage-stage does not appear to increase; however, data regarding the possible impact of the blastocyst-stage preimplantation genetic testing is lacking. We compared the incidence of monozygotic twinning in preimplantation genetic testing cycles performed at the blastocyst-stage, versus cycles without PGT, following single embryo transfer. Methods In this retrospective cohort study, we analyzed the incidence of twin pregnancies in patients undergoing intracytoplasmic sperm injection and blastocyst-preimplantation genetic testing (253 cycles), versus a period-matched control population of patients undergoing intracytoplasmic sperm injection and single embryo transfer without preimplantation genetic testing (606 cycles). Results The overall monozygotic twinning rate was 14/859 (1.6%) per clinical pregnancy. The incidence of zygotic splitting following intracytoplasmic sperm injection and preimplantation genetic testing was 3.5% (95% Confidence interval 1.8%-6.6%) versus 0.8% (95% Confidence interval 0.3%-1.9%) following intracytoplasmic sperm injection without preimplantation sperm injection. After adjusting for potential confounders, preimplantation genetic testing cycles were associated with an increase in the incidence of monozygotic twinning when compared to cycles without embryo biopsy (Odd ratio 3.44, 95% Confidence interval 1.05-11.27, p=0.041). Conclusions Our findings indicate that embryo biopsy for preimplantation genetic testing performed at the blastocyst stage is associated to an increase in the incidence of monozygotic twinning. Further validation in larger sample size studies is warranted. Patients undergoing preimplantation genetic testing must receive proper counselling about the potential risks of the technique.

There is no evidence for the superiority of conventional in vitro fertilization (IVF) or intracytoplasmic sperm injection (ICSI) using donor oocytes. This retrospective descriptive study aimed to c...

Conflicting data have been reported on the comparative doses of recombinant follicle-stimulating hormone (rFSH) and urinary highly purified follicle-stimulating hormone (HP-FSH) required for ovarian stimulation. Nothing is known about the clinical efficacy of rFSH or HP-FSH depending on the N680S follicle-stimulating hormone receptor (FSHR) polymorphism. Our aim was to investigate whether the N680S polymorphism of the FSHR gene affects ovarian response with different forms of FSH.This retrospective cohort study includes 382 cycles performed at Instituto Bernabeu from 191 oocyte donors. All donors carried out two cycles: one with rFSH and the other one with HP-FSH (group 1, n=63), both with HP-FSH (group 2, n=100) or both with rFSH (group 3, n=28). The results were compared by pairs from each patient. The main outcomes were oocyte yield, metaphase II matured oocytes (MII), days of stimulation, and gonadotropin dosage.No significant differences were found when we compared the cycles for donors in group 1. However, according to the FSHR polymorphism, statistical differences were shown. For the SS genotype, more oocytes (16.9 vs. 18.4) and MII (12.8 vs. 15.5) were yielded in the HP-FSH cycle. For the NS genotype, more oocyte (20.1 vs. 16.9) and MII (17.4 vs. 14.2) were yielded in the rFSH cycle. For the NN genotype, no differences were found. No differences were found when we compared the cycles in groups 2 and 3 irrespective of the FSHR polymorphism.For the first time, we have shown in a population of egg donors that the N680S FSHR gene polymorphism affects the efficacy of HP-FSH or rFSH. The FSHR genotype is an important factor to determine the dosage and the nature of the gonadotropin selected for ovarian stimulation.

Recurrent pregnancy loss (RPL; defined as the loss of three or more consecutive pregnancies) and recurrent implantation failure (RIF; when implantation is not achieved after at least three cycles of IVF) are two of the major challenges that reproductive medicine faces. Some polymorphisms have been identified as possible causes of an increased risk of these diseases. This paper studies the prevalence of the polymorphisms in

Chromosomal mosaicism is a relatively common finding in human IVF embryos. However, the association between mosaicism in trophoectoderm and inner mass cells, the mechanisms involved, and its effects on implantation are far from established. We retrospectively reanalyzed array-CGH results from 1,362 trophoectoderm biopsies. We detected chromosomal mosaicism in 183 blastocysts (13.4%). A decrease in the clinical pregnancy rate when we compared the cycles where only mosaic embryos were transferred (26.9%) vs. euploid embryos were transferred (40.2%) was not statistically different (p = 0.127). Also a tendency to increase the biochemical miscarriage was reported (21.2% mosaic group vs. 12.3% euploid group; p=0.102). Our data suggests that the transfer of some mosaic embryos achieve full term pregnancies. Additional studies are needed to clarify how embryo mosaicism affects the outcomes of the IVF cycles.

The human androgen receptor (AR) gene contains a highly polymorphic CAG repeat sequence within exon 1. In-vitro studies have shown a relationship between CAG repeats in the AR gene and its transactivation potential. This variation in length may play a role in anovulatory infertility. The objective of this study was to investigate whether CAG polymorphism of the AR gene has a predictive value for ovarian reserve, response and cycle outcome in an egg donor programme. CAG length of the AR gene was determined in 147 oocyte donors. All donors underwent ovarian stimulation with a gonadotrophin-releasing hormone antagonist protocol (n = 355). No differences were reported in days of stimulation, gonadotrophin doses, and number of oocytes retrieved. Clinical outcomes were not affected by the CAG repeat length of the AR gene; the primary end-point, antral follicle count, was significantly affected (P < 0.05). In conclusion, in a population of fertile egg donors AR gene CAG polymorphism does not affect ovarian response to gonadotrophins. Antral follicle count was associated with the CAG polymorphism genotype. This suggests that genetic factors may increase susceptibility to poor ovarian reserve, and that AR gene genotype could play a role in the natural ovarian ageing process.

Effective controlled ovarian stimulation (COS) is crucial for IVF outcome. Ovarian response to follicle-stimulating hormone, however, varies widely among women undergoing ovarian stimulation. Advance identification of patients who will elicit a poor or high response to standard treatment would be of great clinical benefit for such patients. Application of pharmacogenetics to ovarian response may predict stimulation success but also help in the adjustment and design of doses prior to treatment. Different studies have examined the impact of variations in follicle-stimulating hormone receptor, biochemical pathways involved in estrogen production and action, folliculogenesis and other aspects. Recently, gene-association studies have tried to identify a number of genetic variations affecting interindividual variability in COS.