Random-start ovarian stimulation in an oocyte donation programme: a large, single-centre, experience.

RESEARCH QUESTION: Do live birth rates differ between recipients matched with donors using conventional ovarian stimulation compared with those using random-start protocols? DESIGN: Retrospective analysis of 891 ovarian stimulations in egg donors (January-December 2018) and clinical outcomes in matched recipients (n = 935). Donors commenced ovarian stimulation on day 1-3 of the menstrual cycle (n = 223) or in the mid/late-follicular (n = 388) or luteal phase (n = 280) under a conventional antagonist protocol. Live birth rate of matched recipients was the main outcome. RESULTS: Duration of stimulation and total gonadotrophin dose were comparable between conventional versus random-start groups. The number of collected eggs were similar (17.6 ± 8.8 versus 17.2 ± 8.5, P = 0.6, respectively). Sub-group analysis showed that stimulation length (10.2 ± 1.8 versus 9.8 ± 1.7 versus 10.4 ± 1.7, P < 0.001) and gonadotrophin consumption (2041.5 ± 645.3 versus 2003.2 ± 647.3 versus 2158.2 ± 685.7 IU, P = 0.01) differed significantly between the conventional, mid/late follicular and luteal phase groups, respectively. In matched recipients receiving fresh oocytes and undergoing fresh embryo transfer, the biochemical pregnancy (63.8% and 63.3%; P = 0.9), clinical pregnancy (54.6% and 56.1%; P = 0.8) and live birth rates (47.7% and 46.6%; P = 0.7) per embryo-transfer were similar between conventional versus random groups. Similar results were obtained in recipients receiving vitrified eggs. Euploidy rate was also comparable. CONCLUSIONS: No notable variations were found in clinical outcomes using oocytes obtained from random-start protocols and those proceeding from conventional ovarian stimulation in oocyte donation treatments. Luteal-phase stimulation seems to require longer stimulation and higher FSH consumption. Random-start stimulation strategy does not impair the potential of the oocyte yield or clinical outcomes in oocyte donation cycles.

Does mRNA COVID-19 vaccination in oocyte donors impact ovarian stimulation parameters or IVF outcomes for recipients?

RESEARCH QUESTION: What is the effect of mRNA severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2) vaccination in young oocyte donors in terms of ovarian response to stimulation, fertilization rate, embryo development and clinical outcomes in recipients? DESIGN: This retrospective, multicentre cohort study evaluated 115 oocyte donors who had undergone at least two ovarian stimulation protocols (before and after complete SARS-CoV-2 vaccination) between November 2021 and February 2022. Comparisons were made of the primary outcomes of days of stimulation, total dose of gonadotrophins and laboratory performance in ovarian stimulation in oocyte donors before and after vaccination. A total of 136 cycles in matched recipients were analysed as secondary outcomes and, from those, 110 women received a fresh single-embryo transfer, with analysis of biochemical ß-human chorionic gonadotrophin concentrations and rates of clinical pregnancy with heartbeat. RESULTS: Longer stimulation was required in the post-vaccination than pre-vaccination group (10.31 ± 1.5 versus 9.51 ± 1.5 days; P < 0.001) along with higher gonadotrophin consumption (2453.5 ± 740 versus 2235.5 ± 615 IU; P < 0.001) with a similar starting dose of gonadotrophins in both groups. More oocytes were retrieved in the post-vaccination group (16.62 ± 7.1 versus 15.38 ± 7.0; P = 0.02). However, the number of metaphase II (MII) oocytes was similar between groups (pre-vaccination 12.61 ± 5.9 versus post-vaccination 13.01 ± 6.6; P = 0.39) and the ratio of MII/retrieved oocytes favoured the pre-vaccination group (0.83 ± 0.1 versus 0.77 ± 0.2 post-vaccination; P = 0.019). In recipients with a similar number of provided oocytes, the fertilization rate, total number of obtained blastocysts, number of top-quality blastocysts, and rates of biochemical pregnancy and clinical pregnancy with heartbeat were not significantly different between groups. CONCLUSIONS: This study shows no adverse influence of mRNA SARS-CoV-2 vaccination on ovarian response in a young population.

Noninvasive preimplantation genetic testing using the embryo spent culture medium: an update.

PURPOSE OF REVIEW: The presence of cell-free DNA (cf-DNA) in the embryo spent culture medium allows to develop a noninvasive PGT-A (niPGTA). Noninvasive PGT-A may provide a simpler, safer and less costly approach to preimplantation genetic testing of aneuploidy (PGT-A). Furthermore, niPGTA would provide wider access to embryo genetic analysis and circumvent many legal and ethical considerations. However, the concordance rate between the results obtained by PGT-A and niPGTA varies among studies and, their clinical utility has not been already demonstrated. This review evaluates the niPGTA reliability based on SCM and adds new knowledge about the clinical relevance of SCM for noninvasive PGT-A. RECENT FINDINGS: The most recent concordance studies evaluating the accuracy of niPGTA using SCM showed a high variation in the informativity rate of SCM and the diagnostic concordance. Also, sensitivity and specificity showed similar heterogeneous results. Therefore, these results do not support the clinical utility of niPGTA. Regarding clinical outcome, the data are initial and further research, including randomized and nonselection studies are needed. SUMMARY: Further research, including randomized and nonselection studies, as well as optimization of embryo culture conditions and medium retrieval, are needed to improve the reliability and clinical utility of niPGTA.

FSH receptor genotype and its influence on the results of donor ovarian stimulation using corifollitropin alfa.

RESEARCH QUESTION: Does the FSH receptor (FSHR) genotype influence the results of donor ovarian stimulation using corifollitropin alfa? DESIGN: A prospective cohort study was performed including 152 oocyte donor ovarian stimulations: group 1 (n = 80) using a single dose of 150 µg of corifollitropin alpha; and group 2 (n = 72) using in addition to corifollitropin alpha, continued stimulation using recombinant FSH 225 IU daily. Allelic discrimination was used to genotype the FSHR p.N680S polymorphism. Linear regression analysis was performed to study the differences between groups. RESULTS: No differences in clinical characteristics between genotypes were reported. Overall, the results of ovarian stimulation were better in oocyte donors with SN and NN genotypes compared with SS in terms of the number of retrieved oocytes (15.78 versus 10.83; P = 0.008) and retrieved metaphase II (MII) oocytes (12.34 versus 9.00; P = 0.032). Corresponding differences were also observed in group 1 for the number of retrieved oocytes (13.83 versus 7.50, P = 0.018) and retrieved MII oocytes (10.24 versus 5.42; P = 0.038). However, in group 2 no significant differences were found for oocytes retrieved (17.55 versus 13.06, P = 0.064) or MII oocytes (14.25 versus 11.39; P = 0.12). CONCLUSIONS: This study suggests that ovarian stimulation protocols with corifollitropin alfa in women with the SS genotypes could be associated with fewer oocytes and MII oocytes retrieved. Despite the fact that corifollitropin alfa has a longer half-life, the results for the SS genotype do not match those for the other genotypes, so other factors must be involved. Therefore, to tailor treatments, it would be advisable to genotype women at p.N680S of the FSHR.

Vitrification does not affect birth weight: lessons from the oocyte donation model.

RESEARCH QUESTION: Is embryo cryopreservation a cause of high birth weight and large for gestational age (LGA) in singletons resulting from vitrified-warmed embryo transfer? DESIGN: 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. RESULTS: 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. CONCLUSION: This study eliminates potential confounders that might influence fetal growth and demonstrates that embryo vitrification and warming procedures do not affect birth weight.

Consistent results of non-invasive PGT-A of human embryos using two different techniques for chromosomal analysis.

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.

Luteal phase stimulation versus follicular phase stimulation in poor ovarian responders: results of a randomized controlled trial.

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.

Ovarian hyperstimulation syndrome following GnRH agonist trigger for final follicular maturation in a patient undergoing random start ovarian stimulation for egg-donation cycle with an inadvertent concomitant early pregnancy.

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).

The relevance of the individual screening for genetic variants in predicting ovarian response.

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 vs 14.7 ± 6.2 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.

Effect of the vaginal microbiome on the pregnancy rate in women receiving assisted reproductive treatment.

PURPOSE: To investigate if the vaginal microbiome influences the IVF outcome. METHODS: Thirty-one patients undergoing assisted reproductive treatment (ART) with own or donated gametes and with cryotransfer of a single euploid blastocyst were recruited for this cohort study. Two vaginal samples were taken during the embryo transfer procedure, just before transferring the embryo. The V3 V4 region of 16S rRNA was used to analyze the vaginal microbiome, and the bioinformatic analysis was performed using QIIME2, Bioconductor Phyloseq, and MicrobiomeAnalyst packages. Alpha diversity was compared between groups according to the result of the pregnancy test. RESULTS: Fourteen (45.2%) patients did not and seventeen (54.8 %) did achieve pregnancy under ART. A greater index of alpha diversity was found in patients who did not achieve pregnancy comparing to those who did, although this difference was not significant (p = 0.088). In the analysis of beta diversity, no statistically significant differences were observed between groups established as per the pregnancy status. Samples from women who achieved pregnancy showed a greater presence of Lactobacillus spp. The cluster analysis identified two main clusters: the first encompassed the genera Lactobacillus, Gardnerella, Clostridium, Staphylococcus, and Dialister, and the second included all other genera. Women who achieved pregnancy were mainly detected microorganisms from the first cluster. CONCLUSIONS: The vaginal microbiome can influence the results of ART. The profiles dominated by Lactobacillus were associated with the achievement of pregnancy, and there was a relationship between the stability of the vaginal microbiome and the achievement of pregnancy.

Comparison of two closed carriers for vitrification of human blastocysts in a donor program.

The survival of human blastocysts to vitrification with two different carriers is compared. Both vitrification carriers used in this study are in the category of closed carriers, as they completely isolate the samples from direct contact with liquid nitrogen or its vapours during cooling and storage, until warming. This characteristic is appealing because it reduces or eliminates the theoretical risk of cross-contamination during that period of time. The two closed vitrification systems used present very different design and features: in the High Security Vitrification device, the carrier straw containing the embryos is encapsulated inside an external straw before plunging in liquid nitrogen, resulting in thermal insulation during cooling. On the other hand, in the SafeSpeed carrier embryos are loaded in a thin-walled, narrow capillary designed to maximize the thermal transference. Both closed carriers achieved comparable outcomes in terms of survival of blastocysts to the vitrification process, with 97.5% vs. 96.1% survival with HSV and SafeSpeed, respectively. In conclusion, the cooling and warming rates at which these carriers operate, in combination with the cytosolic solute concentration in the cells of the cryopreserved blastocysts attained after a cryoprotectant-loading protocol, result in successful vitrification of human blastocysts for human assisted reproduction.

Clinical efficacy of recombinant versus highly purified follicle-stimulating hormone according to follicle-stimulating hormone receptor genotype.

OBJECTIVE: 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. MATERIALS AND METHODS: 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. RESULTS: 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. CONCLUSION: 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.

Metabolites involved in cellular communication among human cumulus-oocyte-complex and sperm during in vitro fertilization.

BACKGROUND: Fertilization is a key physiological process for the preservation of the species. Consequently, different mechanisms affecting the sperm and the oocyte have been developed to ensure a successful fertilization. Thus, sperm acrosome reaction is necessary for the egg coat penetration and sperm-oolema fusion. Several molecules are able to induce the sperm acrosome reaction; however, this process should be produced coordinately in time and in the space to allow the success of fertilization between gametes. The goal of this study was to analyze the metabolites secreted by cumulus-oocyte-complex (COC) to find out new components that could contribute to the induction of the human sperm acrosome reaction and other physiological processes at the time of gamete interaction and fertilization. METHODS: For the metabolomic analysis, eighteen aliquots of medium were used in each group, containing: a) only COC before insemination and after 3 h of incubation; b) COC and capacitated spermatozoa after insemination and incubated for 16-20 hours; c) only capacitated sperm after 16-20 h in culture and d) only fertilization medium as control. Six patients undergoing assisted reproduction whose male partners provided normozoospermic samples were included in the study. Seventy-two COC were inseminated. RESULTS: The metabolites identified were monoacylglycerol (MAG), lysophosphatidylcholine (LPC) and phytosphingosine (PHS). Analysis by PCR and in silico of the gene expression strongly suggests that the cumulus cells contribute to the formation of the PHS and LPC. CONCLUSIONS: LPC and PHS are secreted by cumulus cells during in vitro fertilization and they could be involved in the induction of human acrosome reaction (AR). The identification of new molecules with a paracrine effect on oocytes, cumulus cells and spermatozoa will provide a better understanding of gamete interaction.

Androgen receptor CAG repeat length is associated with ovarian reserve but not with ovarian response.

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.

Negative effect of P72 polymorphism on p53 gene in IVF outcome in patients with repeated implantation failure and pregnancy loss.

PURPOSE: Investigate whether R72P on p53 gene polymorphism has a higher prevalence among women with a history of recurrent implantation failure (RIF) and pregnancy loss (RPL) and its influence in their IVF cycle outcome. MATERIAL AND METHODS: p53 polymorphism R72P has been studied in 181 women. The control group included 83 oocyte donors. In the study group 98 women were included: 44 with RIF and 54 with RPL. From the study group, 76 patients underwent IVF-cycles (55 RPL and 21 RIF). RESULTS: The frequency of PP genotypes on p53 among RIF was 11.4% compared with 18.5% for RPL and 6% in controls (p < 0.01). There were no significant differences with respect to patient characteristics. Significant differences were reported in pregnancy rate (69.4% for RR/RP and 33.3% for PP; p < 0.05), embryo implantation rate (33.3% for RR/RP and 7.3% for PP; p < 0.05) and ongoing pregnancy rate (53.1% for RR/RP and 14.3% for PP; p < 0.05) among RIF and RPL. CONCLUSIONS: This investigation reveals that in RIF and RPL patients R72P on p53 gene is more prevalent than fertile population. Moreover, patients carrying a PP genotype on p53 codon 72 will have less chance to achieve an ongoing pregnancy. This information together with some additional markers will allow development of diagnostic tests for detects risk for RIF and RPL before infertility treatment is initiated.

Endometrial receptivity in women with endometriosis.

As endometriosis is recognized as a contributing factor to infertility, prompting couples to embark on Assisted Reproductive Technology (ART) treatments, it becomes crucial to comprehend the extent and way this condition can affect success rates. Natural conception data reveal lower success rates for women with endometriosis, yet the same cannot be extrapolated to the outcomes of in vitro fertilization (IVF). In recent years, advancements in the ART process, particularly the distinct stages of the IVF pathway and investigations into embryo quality have shown a comparable rate of embryonic quality and chromosomal normalcy (euploidy) between embryos obtained from individuals with or without endometriosis. Thus, the primary question that lingers relates to the functionality of the endometrium. This review addresses whether endometriosis can influence endometrial receptivity and implantation rates.

The impact of (very) young donor age on euploid rates: An analysis of 1831 trophectoderm biopsies evaluated with 24-chromosome NGS screening in oocyte donation cycles.

RESEARCH QUESTION: Conflicting data exists regarding whether a younger age of donors has a negative influence on the outcomes of oocyte donation cycles. Is there any correlation between a younger age of donors and the rate of embryonic aneuploidy in oocyte donation cycles? DESIGN: Retrospective study including 515 oocyte donation cycles carried out between February 2017 and November 2022. Comprehensive chromosomal screening was performed on 1831 blastocysts. 1793 had a result which were categorised into groups based on the age of the donor: 18-22 (n = 415), 23-25 (n = 600), 26-30 (n = 488), and 31-35 years (n = 290). The analysis aimed to determine the percentage of biopsy samples that were euploid and the number that were aneuploid, relative to the age group of the oocyte donor. Additionally, linear regression was employed to examine the relationship between age and the proportion of aneuploid embryos, while controlling for relevant variables. RESULTS: Aneuploidy increased predictably with donor age: 18-22 years: 27.5 %; 23-25 years: 31.2 %; 26-30 years: 31.8 %; and 31-35 years: 38.6 %. In the donor group aged 31-35 years, a higher percentage of aneuploid embryos was observed compared to younger donors in univariate analysis (OR: 1.66, 95 % CI: 1.21-2.29, p = 0.002) and multivariate logistic analysis (OR: 2.65, 95 % CI: 1.67-4.23, p < 0.001). The rates of embryonic mosaicism revealed no significant differences. CONCLUSION: The lowest risk of embryonic aneuploidy was found among donors aged <22 years. Conversely, an elevated prevalence was evident within the donor group aged 31-35 years, in contrast to the younger cohorts. The incidence of mosaic embryos remained consistent across all age groups.

Exome sequencing in genuine empty follicle syndrome: Novel candidate genes.

OBJECTIVE(S): Empty follicle syndrome (EFS) is a condition in which no oocytes are retrieved in an IVF cycle despite apparently normal follicular development and meticulous follicular aspiration following ovulation induction. The EFS is called genuine (gEFS) when the trigger administration is correct. The existence of gEFS is a subject of controversy, and it is quite rare with an undetermined etiology. Genetic defects in specific genes have been demonstrated to be responsible for this condition in some patients. Our objective was to identify novel genetic variants associated with gEFS. STUDY DESIGN: We conducted a prospective observational study including 1,689 egg donors from July 2017 to February 2023. WES were performed in patients suffering gEFS. RESULTS: Only 7 patients (0.41 %) exhibited gEFS after two ovarian stimulation cycles and we subsequently performed whole exome sequencing (WES) on these patients. Following stringent filtering, we identified 6 variants in 5 affected patients as pathogenic in new candidate genes which have not been previously associated with gEFS before, but which are involved in important biological processes related to folliculogenesis. These genetic variants included c.603_618del in HMMR, c.1025_1028del in LMNB1, c.1091-1G > A in TDG, c.607C > T in HABP2, c.100 + 2 T > C in HAPLN1 and c.3592_3593del in JAG2. CONCLUSION: As a conclusion, we identified new candidate genes related to gEFS that expand the mutational spectrum of genes related to gEFS.This study show that WES might be an efficient tool to identify the genetic etiology of gEFS and provide further understanding of the pathogenic mechanism of gEFS.

Impact of Group vs Individual Embryo Culture Strategies on Blastocyst and Clinical Outcomes.

Embryo culture is one of the most important steps in an assisted reproduction laboratory. Embryos can be cultured individually, one embryo per media drop, or in groups, culturing several embryos in the same media drop. Due to the controversy generated on this subject, we wondered which embryo culture method would have the best results in terms of quality and blastocyst formation rate. We designed a prospective randomized study comparing two different embryo culture strategies: group and individual embryo culture. The data were obtained from 830 embryos from 103 egg donation treatments. The zygotes were randomized into two groups: individual culture (group 1) or group culture (group 2). The embryos were cultured in 35-µl drops until day 5 when they were classified morphologically. We observed a significant increase in the blastocyst formation rate and in the usable embryo rate in individual culture on day 5 compared to group culture. However, good embryo quality (A/B blastocysts), implantation, and pregnancy rates were similar regardless of the type of embryo-culture. As a conclusion, individual culture may increase blastocyst formation rate and may benefit embryo quality on day 5. Our results support previous reports suggesting that individual culture could improve embryo development.

Effect of follicle-stimulating hormone receptor N680S polymorphism on the efficacy of follicle-stimulating hormone stimulation on donor ovarian response.

OBJECTIVE: The aim of this study was to investigate whether N680S FSHR polymorphism has a predictive value for the ovarian response to stimulation with gonadotropins and cycle outcome in our egg donor program. METHODS: The oocyte donor candidates were selected according to the Instituto Bernabeu egg donation program requirements and ASRM and ESHRE guidelines for oocyte donation. The FSHR polymorphism N680S was studied in 145 oocyte donors. All donors underwent controlled ovarian hyperstimulation (COH) (n=355) using urinary follicle-stimulating hormone in a GnRH antagonist protocol and receiving a GnRH agonist triggering. The main outcome measures were oocyte yield, days of stimulation, gonadotropin doses, biochemical pregnancy, ongoing pregnancy, and miscarriage rates. RESULTS: Significant differences were reported in the antral follicle count (16.5 ± 5.0 for NN, 14.5 ± 4.7 for NS, and 14.1 ± 3.8 for SS), number of eggs retrieved (21.5 ± 9.2 for NN, 18.5 ± 8.2 for NS, and 19.8 ± 8.9 for SS), and gonadotropin doses (2098.5 ± 639.4 IU for NN, 2023 ± 490.1 IU for NS, and 2149.5 ± 552.3 IU for SS) between the genotypes. The clinical outcome was not affected by the N680S polymorphism of the FSHR gene in the egg donors. CONCLUSION: In a population of fertile egg donors, the FSHR gene polymorphism at position 680 is associated with different ovarian responses to COH. The genotype of the FSHR gene is an important factor for determining the prognosis of the COH cycles in normo-ovulatory fertile women.