Too many embryos: a critical perspective on a global challenge.

Over the past decade, significant endeavors have been directed toward establishing an optimal oocyte number to maximize the chances for successful in vitro fertilization outcomes. The effectiveness of assisted reproductive technologies has greatly improved, and more good-quality embryos are being created in each cycle. However, many of these embryos remain unused. Notably, in Europe, approximately one-third of couples did not use their surplus cryopreserved embryos. Surplus embryos pose a challenge for patients and clinics. Embryo disposal practices are not the same all over the continent, with embryo donation and embryo discharge not allowed in several countries. In this scenario, limiting the number of surplus embryos by reducing the number of inseminated oocytes, according to couple clinical history, could be a strategy.

Assessing the developmental competence of oocytes matured following rescue in vitro maturation: a systematic review and meta-analysis.

PURPOSE: To assess the developmental competence of oocytes matured following rescue in vitro maturation (IVM). METHODS: PubMed, EmBASE, and SCOPUS were systematically searched for peer-reviewed original papers using relevant keywords and Medical Subject Heading terms. Study quality was assessed using the Newcastle-Ottawa Scale. Odds ratios with a 95% confidence interval were calculated by applying a random effects model. The primary outcomes were fertilization and blastulation rates. Secondary outcomes included abnormal fertilization, cleavage, euploidy, clinical pregnancy, and live-birth rates. RESULT: Twenty-four studies were included in the meta-analysis. The oocytes matured following rescue IVM showed significantly reduced fertilization, cleavage, blastulation, and clinical pregnancy rates compared to sibling in vivo-matured oocytes. No significant differences were found for the euploidy and live-birth rates in euploid blastocyst transfer. In poor responders, a reduced fertilization rate was observed using in vitro-matured GV but not with in vitro-matured MI. A reduced cleavage rate in MI matured overnight compared to < 6 incubation hours was found. CONCLUSION: Our results showed compromised developmental competence in oocytes matured following rescue IVM. However, in poor responders, rescue IVM could maximize the efficiency of the treatment. Notably, our data suggests using in vitro MI matured within 6 incubation hours. CLINICAL TRIAL REGISTRATION NUMBER: CRD42023467232.

Low-molecular-weight heparin in the prevention of unexplained recurrent miscarriage: a systematic review and meta-analysis.

The etiology of recurrent pregnancy loss (RPL) is complex and multifactorial and in half of patients it remains unexplained (U-RPL). Recently, low-molecular-weight heparin (LMWH) has gained increasing relevance for its therapeutic potential. On this regard, the aim of this systematic review and meta-analysis is to analyze the efficacy of low molecular weight heparin (LMWH) from the beginning of pregnancy in terms of live birth rates (LBR) in U-RPL. Registered randomized controlled trials (RCTs) were included. We stratified findings based on relevant clinical factors including number of previous miscarriages, treatment type and control type. Intervention or exposure was defined as the administration of LMWH alone or in combination with low-dose aspirin (LDA). A total of 6 studies involving 1016 patients were included. The meta-analysis results showed that LMWH used in the treatment of U-RPL was not associated with an increase in LBR with a pooled OR of 1.01, a medium heterogeneity (26.42%) and no publication bias. Results of other sub-analyses according to country, treatment type, and control type showed no significant effect of LMWH on LBR in all subgroups, with a high heterogeneity. The results highlight a non-significant effect of LMWH in U-RPL on LBR based on moderate quality evidence.Registration number: PROSPERO: ( https://www.crd.york.ac.uk/prospero/display_record.php?ID=CRD42022326433 ).

The effect of laser-assisted hatching on vitrified/warmed blastocysts: the ALADDIN randomized controlled trial.

OBJECTIVE: To evaluate whether laser-mediated assisted hatching (AH) performed on vitrified/warmed blastocysts before embryo transfer can improve live birth rate. DESIGN: The "pArtiaL zonA pelluciDa removal by assisteD hatchINg of blastocysts (ALADDIN)" is a 2-center comparative study with a parallel randomized controlled design. SETTING: University hospital. PATIENTS: Participants were recruited between September 2018 and November 2021. They were aged 18-39 years, underwent nondonor in vitro fertilization cycles, and were scheduled for elective single embryo transfer with vitrified/warmed blastocysts. Those with uterine abnormalities, body mass index of >35 kg/m2, severe male factor infertility, or performing preimplantation genetic testing were excluded. INTERVENTION: Assisted hatching was performed using a 1,480 nm diode laser, removing approximately one-third of the zona pellucida with continuous 0.2 ms pulses applied from the 1-5 o'clock positions. MAIN OUTCOME MEASURES: The primary outcome was the live birth rate. Secondary end points included clinical pregnancy, miscarriage, multiple pregnancies, preterm births, obstetric and neonatal complications, and congenital anomalies. RESULTS: Overall, 698 participants met the inclusion criteria and were randomized: 352 patients were assigned to the AH arm and 346 to the control arm. Of the participants, 105 (29.8%) and 101 (29.2%), respectively, achieved a live birth after treatment. The relative risk of live birth in patients with vitrified/warmed blastocysts treated with AH was 1.02 (95% confidence interval, 0.86-1.19). Exploratory subgroup analyses for women's age, recruiting centers, indications for in vitro fertilization, method of insemination, blastocyst quality, and days of blastocyst development failed to highlight any clinical situation that could benefit from AH in thawed blastocysts. CONCLUSION: In patients undergoing frozen embryo transfer with vitrified/warmed blastocysts, laser AH does not improve the live birth rate. Further studies are required to rule out milder but potentially interesting benefits in specific subgroups of patients. TRIAL REGISTRATION: ClinicalTrials.gov: NCT03623659.

Thinking in context: Fibroids-to-uterine volume ratio in pre-surgical fertility evaluation for intramural fibroids.

OBJECTIVE: To explore the utility of the total fibroids-to-uterine volume (FTUV) ratio as a simple, preoperative tool to assist in counseling patients seeking pregnancy who are undergoing myomectomy for intramural (IM) fibroids. STUDY DESIGN: This is an historical cohort study on reproductive-aged patients seeking pregnancy who underwent laparotomic myomectomy for intramural fibroids from January 2017 to December 2021. Only G3 to G5 fibroids, according to the 2011 International Federation of Gynecology and Obstetrics (FIGO) classification, were included. Pre-operative transvaginal ultrasound (TVUS) was performed to measure the volume of intramural myomas (diameter1*diameter2*diameter3*0.52) and to calculate their total volume. The total fibroids-to-uterine volume (FTUV) ratio was calculated as the proportion of the uterine volume occupied by the sum of IM fibroids volumes. RESULTS: A total of 166 women with pre-surgical TVUS evaluation of IM fibroids were included, with a mean age of 36.22 ± 5.15 years. The FTUV ratio was identified as a positive predictor of clinical pregnancy after surgery (adjOR, 1.04; 95 % CI, 1.02-1.06; p = 0.0001), whereas age showed a negative association (adjOR, 0.90; 95 % CI, 0.83-0.98; p = 0.012). Endometrial cavity distortion prior to surgery was also positively associated with pregnancy post-surgery (adjOR, 3.50; 95 % CI, 1.51-8.08; p = 0.003). Consistent results were found for live births, with the FTUV ratio being a significant positive predictor of live birth after surgery (adjOR, 1.03; 95 % CI, 1.01-1.05; p = 0.001) and age showing a negative association (adjOR, 0.88; 95 % CI, 0.80-0.96; p = 0.004). Parity prior to surgery also positively impacted live birth post-surgery (adjOR, 2.65; 95 % CI, 1.30-5.40; p = 0.007). An FTUV ratio threshold of 53.39 % accurately predicted clinical pregnancy in 68.46 % of cases (sensitivity of 71.70 % and specificity of 66.67 %). For live births, a higher FTUV ratio threshold of 59.21 % predicted outcomes accurately in 69.13 % of cases (sensitivity of 65.85 % and specificity of 70.37 %). CONCLUSION: The use of the FTUV ratio in pre-operative ultrasound evaluation of IM fibroids may improve counseling for patients desiring to conceive after myomectomy. By providing a personalized assessment of the amount of myometrial volume occupied by fibroids, the FTUV ratio can help predict fertility outcomes after surgery, enabling better-informed decisions and treatment planning.

Extracellular vesicles secreted by human aneuploid embryos present a distinct transcriptomic profile and upregulate MUC1 transcription in decidualised endometrial stromal cells.

STUDY QUESTION: Do extracellular vesicles (EVs) secreted by aneuploid human embryos possess a unique transcriptomic profile that elicits a relevant transcriptomic response in decidualized primary endometrial stromal cells (dESCs)? SUMMARY ANSWER: Aneuploid embryo-derived EVs contain transcripts of PPM1J, LINC00561, ANKRD34C, and TMED10 with differential abundance from euploid embryo-derived EVs and induce upregulation of MUC1 transcript in dESCs. WHAT IS KNOWN ALREADY: We have previously reported that IVF embryos secrete EVs that can be internalized by ESCs, conceptualizing that successful implantation to the endometrium is facilitated by EVs. Whether these EVs may additionally serve as biomarkers of ploidy status is unknown. STUDY DESIGN SIZE DURATION: Embryos destined for biopsy for preimplantation genetic testing for aneuploidy (PGT-A) were grown under standard conditions. Spent media (30 µl) were collected from euploid (n = 175) and aneuploid (n = 140) embryos at cleavage (Days 1-3) stage and from euploid (n = 187) and aneuploid (n = 142) embryos at blastocyst (Days 3-5) stage. Media samples from n = 35 cleavage-stage embryos were pooled in order to obtain five euploid and four aneuploid pools. Similarly, media samples from blastocysts were pooled to create one euploid and one aneuploid pool. ESCs were obtained from five women undergoing diagnostic laparoscopy. PARTICIPANTS/MATERIALS SETTING METHODS: EVs were isolated from pools of media by differential centrifugation and EV-RNA sequencing was performed following a single-cell approach that circumvents RNA extraction. ESCs were decidualized (estradiol: 10 nM, progesterone: 1 µM, cAMP: 0.5 mM twice every 48 h) and incubated for 24 h with EVs (50 ng/ml). RNA sequencing was performed on ESCs. MAIN RESULTS AND THE ROLE OF CHANCE: Aneuploid cleavage stage embryos secreted EVs that were less abundant in RNA fragments originating from the genes PPM1J (log2fc = -5.13, P = 0.011), LINC00561 (log2fc = -7.87, P = 0.010), and ANKRD34C (log2fc = -7.30, P = 0.017) and more abundant in TMED10 (log2fc = 1.63, P = 0.025) compared to EVs of euploid embryos. Decidualization per se induced downregulation of MUC1 (log2fc = -0.54, P = 0.0028) in ESCs as a prerequisite for the establishment of receptive endometrium. The expression of MUC1 transcript in decidualized ESCs was significantly increased following treatment with aneuploid compared to euploid embryo-secreted EVs (log2fc = 0.85, P = 0.0201). LARGE SCALE DATA: Raw data have been uploaded to GEO (accession number GSE234338). LIMITATIONS REASONS FOR CAUTION: The findings of the study will require validation utilizing a second cohort of EV samples. WIDER IMPLICATIONS OF THE FINDINGS: The discovery that the transcriptomic profile of EVs secreted from aneuploid cleavage stage embryos differs from that of euploid embryos supports the possibility to develop a non-invasive methodology for PGT-A. The upregulation of MUC1 in dESCs following aneuploid embryo EV treatment proposes a new mechanism underlying implantation failure. STUDY FUNDING/COMPETING INTERESTS: The study was supported by a Marie Sklodowska-Curie Actions fellowship awarded to SM by the European Commission (CERVINO grant agreement ID: 79620) and by a BIRTH research grant from Theramex HQ UK Ltd. The authors have no conflicts of interest to declare.

Contemporary Diagnostic Work-Up for Male Infertility: Emphasizing Comprehensive Baseline Assessment.

Infertility is a prevalent issue affecting many couples during their reproductive years, with a significant number facing challenges in conceiving despite regular unprotected intercourse. Male factor infertility (MFI) contributes significantly to these cases, with a significant proportion of men lacking an identifiable etiology. As such, a thorough assessment of MFI has become increasingly vital for personalized management. This position paper from the Andrology team at IRCCS Ospedale San Raffaele emphasizes a comprehensive and individualized approach to MFI work-up, addressing the evolving challenges encountered in clinical practice. Our approach involves a thorough diagnostic work-up to identify the underlying causes of MFI, integrating insights from extensive literature review and our proprietary data. Our data demonstrates that an extensive diagnostic assessment allows us to identify at least one underlying cause of MFI in most infertile men. However, challenges persist in diagnosing less severe phenotypes with unclear etiology. We discuss the importance of individualized MFI work-up and its implications for developing rational therapeutic protocols. Lastly, this paper highlights the necessity for a personalized diagnostic assessment, addressing the daily clinical challenges and emphasizing tailored approaches to try to improve outcomes among couples seeking first medical help for infertility.

To Assess or Not to Assess: Reconsidering Day 3 Embryo Quality in Planned Freeze-All Blastocyst Cycles.

Day 3 embryo quality is a predictor of in vitro fertilization (IVF) success rates in cleavage-stage embryo transfer. However, the association between day 3 embryo quality and clinical outcomes in blastocyst transfer policy is largely unknown. This retrospective study included 1074 frozen-thawed single day 5/6 blastocyst transfers between January 2019 and December 2022. Three groups were assessed depending on whether the transferred blastocyst derived from a top-quality, good-quality, or poor-quality embryo at day 3. The analysis was conducted independently for each blastocyst quality group (top, good, and poor) using multivariable logistic regression. We applied a Factorial Analysis of Mixed Data (FAMD) to reduce the potential collinearity between the covariates used in the model. All the blastocysts included in this study were obtained from the first ICSI freeze-all cycles. The cleavage and blastocysts stages were assessed between 67 ± 0.5 (day 3), 115 ± 0.5 (day 5), and 139 ± 0.5 (day 6) hours post-insemination (hpi), respectively. After adjusting for the day of transfer (day 5 or day 6) and FAMD dimensions, no statistical differences in a ß-HCG, clinical pregnancy, and live birth were observed among the same-quality blastocysts derived from different day 3 embryo quality groups (top = A, good = B, and poor = C). Our findings showed that a day 3 embryo quality assessment may be unnecessary in planned freeze-all blastocyst cycles.