Abstract Study question How effective and safe is freeze-all blastocyst transfer in combination with late rescue intracytoplasmic sperm injection (r-ICSI)? Summary answer Freeze-all blastocyst stage embryo transfer (ET) serves as an optimal strategy to support late r-ICSI. What is known already Late r-ICSI has not been widely adopted due to the time-dependent in vitro deterioration of oocyte quality and endometrial growth not being synchronised with embryo development. Study design, size, duration This was a retrospective cohort study. All participants received treatment between 2009 and 2019. 2,270 patients in the aggregate encountered unexpected total fertilisation failure (TFF) during 149,054 cycles of in vitro fertilisation (IVF) and adopted a late r-ICSI procedure, whilst meeting the inclusion criteria for this study. Participants/materials, setting, methods Patients were grouped according to transfer strategies (926 women in Group 1 underwent fresh ET, 365 women in Group 2 underwent freeze-all ET, 716 women in Group 3 experienced blastulation failure, and 263 women did not have available D3 embryos). Patients received different ET strategies after r-ICSI, with the main outcome measures included live birth rate (LBR), cumulative live birth rate (cLBR), and conservative cLBR. Main results and the role of chance TFF occurred in 7.4 % of all IVF cycles. Group 1 tended to be older at oocyte retrieval [33.00 (30.00–37.00) vs. 31.00 (29.00–35.00), P < 0.001], with more infertile years [5.00 (3.00–8.00) vs. 3.00 (2.00–6.00), P < 0.001], higher follicle-stimulating hormone (FSH) levels [7.10 (5.71–8.69) vs. 6.61 (5.25–7.95) mIU/mL, P < 0.001], higher gonadotropin consumption [2850.00 (1950.00–4125.00) vs. 2325.00 (1800.00–3150.00) IU, P < 0.001], and fewer oocytes retrieved [10.00 (6.00–15.00) vs. 13.00 (9.00–19.00), P < 0.001]. Group 2 exhibited considerably better LBRs following the first ET cycle (37.53 % vs. 4.64 %) and cLBR (52.60 % vs. 8.21 %). After adjustment for covariates using binary logistic regression analyses, Group 2 still showed better obstetric performance in LBR (OR:11.77, 95 % CI (8.42–16.45)], cLBR (OR:11.29, 95 % CI (7.84–16.27)], and conservative cLBR (OR:2.55, 95 % CI (1.83–3.55)]. Additionally, the two groups showed similar miscarriage rates, whilst no new-borns with malformations or congenital diseases were reported. Limitations, reasons for caution This study was based on a retrospective cohort, which is inevitably associated with a skewed data distribution and inherent biases. Wider implications of the findings Our study highlights r-ICSI as a safe and effective alternate solution for unexpected TFF to aid frustrated couples. However, for women with limited oocytes available for r-ICSI use, weighing the benefits against the costs of the procedure might be prudent before implementing in vitro blastulation. Trial registration number NA

Abstract Study question How do seven progestogen regimens rank in their efficacy for achieving clinical pregnancy when used as luteal support in women undergoing fresh embryo transfer? Summary answer Given as luteal support and based on clinical pregnancy rate, intramuscular progesterone was most effective, followed by oral dydrogesterone and then micronized vaginal progesterone gel. What is known already A large number of randomized controlled trials (RCTs) have compared fresh in vitro fertilisation cycle luteal support with progestogens. A number of systematic reviews and conventional meta-analyses have likewise been published. A network meta-analysis integrates direct and indirect comparisons between treatments in a single analysis, and allows the ranking of treatments and the estimation of heterogeneity in both the effect of any given treatment and the inconsistency (‘incoherence') in the evidence from different pairs of treatments. Network meta-analyses can thus increase the precision and robustness of inferences from the literature on treatment effect estimates. Study design, size, duration A literature search was performed using BIOSIS, Embase, and MEDLINE and supplemented with manual searches to identify RCTs reporting the efficacy of progestogen regimens in luteal support during fresh embryo transfer. A single network meta-analysis was used to compare progestogen regimens, combining both direct and indirect evidence across the selected studies using the R package ‘netmeta’ and fixed and random effects models. The analysis was repeated and confirmed using SAS. Participants/materials, setting, methods Peer-reviewed full publications that compared individual progestogens (either with placebo or another progestogen) were included. Studies were excluded if they included frozen embryo transfers, used human chorionic gonadotropin or formulations not currently available for the indication, or if they did not report at least clinical pregnancy rate. Two authors (EK, QW) individually reviewed papers to collect data. Where doses differed between studies for an individual progestogen the doses were noted and the results combined. Main results and the role of chance Among studies from 1987–2022, 35 RCTs met the inclusion criteria, comprising 17,955 observations of 7 treatments plus placebo and resulting in 43 pairwise comparisons for the network meta-analysis of clinical pregnancy rate (the primary outcome). Based on the random effects model, the top three regimens versus placebo were intramuscular (IM) progesterone, Duphaston® (oral dydrogesterone), and Crinone® (micronized progesterone vaginal gel) (see Figure). Compared with placebo, only the top 3 ranking compounds had confidence intervals that excluded zero, with a risk difference to placebo (95% confidence interval) of 0.08 (0.01-0.14) for IM progesterone and 0.07 (0.01-0.13) for both Duphaston® and Crinone®. The P-score (fixed, random) ranking for the compounds was: IM progesterone 0.77, 0.79; Duphaston® 0.78, 0.69; Crinone® 0.65, 0.65; Cyclogest® (vaginal micronized progesterone) 0.58, 0.60; Endometrin® (vaginal micronized progesterone) 0.52, 0.54; Prolutex® (subcutaneous progesterone) 0.31, 0.36; Utrogestan® (vaginal micronized progesterone) 0.34, 0.31; and placebo 0.05, 0.06. Ranking was confirmed by SUCRA score (surface under the cumulative ranking curve). Studies were thoroughly reviewed to ensure similarity assumption. Homogeneity and consistency of the network were investigated and fulfilled. Exclusion of placebo-controlled studies did not impact the overall results or rankings. Limitations, reasons for caution Treatment duration was assumed identical across arms in each study and therefore was not included in this analysis. Most studies were single-centre with a small sample size. Methodological rigor was heterogenous between trials. Direct comparisons with placebo were only available for the top three compounds. Wider implications of the findings Three progestogen regimens showed a positive effect on clinical pregnancy rate versus placebo. Frequently used vaginal preparations do not lead the efficacy league table when the available direct and indirect comparative evidence is collated. Relevant efficacy differences likely exist between the available progesterone regimens. Trial registration number n/a

Abstract Study question What are predictors of successful sperm retrieval (SRR) with microdissection testicular sperm extraction (mTESE) in men with non-obstructive azoospermia (NOA) according to different etiologies? Summary answer Predictors for SRR were different in patients with various etiologies and effects of age on SRR in idiopathic NOA and KS patients were opposite. What is known already NOA patients due to spermatogenic dysfunction, accounting for about 60 percent of the total azoospermia cases, may have opportunities to obtain sperm by mTESE and overall SRR of mTESE in NOA patients is about 50%. There were some of predictive factors for SRR at mTESE including age, testis volume, serum follicle stimulating hormone (FSH), testosterone (T), inhibin B, anti-Mullerian hormone and testicular histopathology, while the predictive factors of SRR remains underappreciated, especially in accordance with different type of etiology. Most notably, there are some controversies about the relationship between SSR and age at mTESE surgery. Study design, size, duration This retrospective study involved 3104 NOA patients with different etiologies treated with the first mTESE at the Reproductive Medical Centre of Peking University Third Hospital from March 2012 to December 2022. Participants/materials, setting, methods 3104 NOA patients were classified into seven groups according to etiologies including 1530 males with idiopathic NOA (iNOA), 763 males with Klinefelter syndrome (KS), 345 males with microdeletion of the AZFc, 177 cases with the history of cryptorchidism, 131 with a history of mumps orchitis, 89 males with cryptozoospermia and 69 cases with other causes. The end-point was the presence of one or more sperm. Multi-variable logistic regression was used to analyze sperm retrieval outcome. Main results and the role of chance Overall SRR was 43.46%, and there were different SRR in NOA patients with various etiologies with highest SRR of 89.31% in patients with a history of mumps orchitis and lowest SRR of 29.35% in iNOA patients. For patients with a history of mumps orchitis, there was a negative relationship between T and SRR (0.805 [0.654, 0.991] p = 0.041). For cryptozoospermia patients, shorter infertility duration was predictive for successful SRR (0.837 [0.704, 0.995], p = 0.044). Males with bigger testes had more likelihood of positive SRR (1.077 [1.005; 1.153], p = 0.035) in patients with cryptorchidism. BMI was an independent factor of SRR in AZFc-deleted patients (1.084 [1.013, 1.161], p = 0.020). For KS patients, lower male age (0.938 [0.898, 0.979], p = 0.004) and bigger testes (1.214[1.099, 1.342], p＜0.001) were predictive for successful SRR. Lower levels of FSH (0.984[0.970, 0.998] p = 0.025) and higher male age(1.079[1.050, 1.110], p＜0.001) were predictive for successful sperm retrieval in iNOA patients. So, the optimum age range of iNOA male undergoing mTESE should be 30 to 35 years old with the SRR of 29.13% when considering low SRR of iNOA males aged＜30 years (23.96%) and the negative effect of female age on ICSI outcome. Limitations, reasons for caution Surgeon performing mTESE maybe another predictor for SRR which is a potential selection bias. Inhibin B and Anti-Müllerian hormone weren’t included due to limited information in our database. We couldn’t verify the conclusion in more population from multicenter despite the current study with the large sample size so far. Wider implications of the findings Our results provide valuable information for NOA patients who want to counsel surgeons about their treatments to help patients and surgeons to perform a shared decision-making for optimal therapy methods, especially about optimal age treated with mTESE in iNOA and KS patients. Trial registration number not applicable

Preimplantation genetic testing for monogenic diseases (PGT-M) is available for any single gene defects theoretically, as long as the disease-causing locus has been unequivocally identified. However, PGT-M has faced great challenges for couples with more than one genetic mutation, de novo mutations or without essential family members for linkage analysis. In order to overcome these challenges, we developed a comprehensive strategy which includes preimplantation genetic testing for aneuploidies (PGT-A) and chromosomal structural rearrangements (PGT-SR) study, as well as monogenic diagnosis study for couples bearing de novo mutations or without necessary familial members. The innovation of our strategy is to use the gamete (polar body or single sperm) or embryo as proband for linkage analyses (GEPLA) to detect an embryo’s carrier status. GEPLA strategy uses affected embryo as proband or gametes carrying mutant alleles as proband for SNP linkage analyses, that were suitable for all types of patients mentioned above. Using this novel developed method, nine autosomal dominant polycystic kidney disease (ADPKD) couples with either de novo mutation or without a positive family history were recruited. Moreover, other two couples with single gene disorders (SMA and NF2) which lack of essential family members for linkage analysis including de novo mutation, and also combined with reciprocal translocation were recruited too. For nine ADPKD couples, a total of 34 embryos from 13 PGT-M cycles were examined and two couples were successfully delivered healthy babies. For the other two couples, 15 embryos were screened, and two embryos were determined as free of the monogenic disease and specific chromosomal abnormalities created by reciprocal translocations. This study provides a creative approach for embryo diagnosis of patients with de novo mutations or patients lacking of essential family members for linkage analysis, and even for reciprocal chromosome translocation concurrently.