Research question: Are authors aware when they have cited a retracted paper in their manuscripts in the medically assisted Design: A cross-sectional study based on an online survey was conducted to acquire information on the citation pattern from corresponding authors who had cited a retracted article. A dataset of retracted articles in the MAR field was collected from PubMed and Retraction Watch. A complete list of published articles that cited each retracted article was retrieved. The survey was distributed via e-mail to corresponding authors who had cited a retracted paper in their study. Results: The survey revealed a significant lack of awareness among authors, with 78.7% unaware that they had cited retracted articles. This lack of awareness was attributed to insufficient notification mechanisms within research databases and journals, alongside a reliance on previously stored copies of manuscripts. A notable finding was that reference checks were typically performed by a single author, with no instances of retraction concerns raised during the peer-review process. Only a small fraction (17.8%) of respondents reported verifying retraction notices on both journal websites and scientific databases. Conclusions: Correcting publications that contain references which are subsequently retracted is significant for systematic reviews, meta-analyses and guidelines. Citations of retracted articles perpetuate erroneous scientific data, but assessing the accuracy of citations requires considerable effort. Proper notification of retraction status and cross-checking of citations can help to prevent errors.

Research question: Does ejaculatory abstinence impact fertilization outcomes in intracytoplasmic sperm injection (ICSI) cycles in infertile couples? Design: This single -centre retrospective observational study included 6919 ICSI cycles from 2013 to 2022. The primary outcome was the assessment of oocyte fertilization, measured in terms of the rate of formation of two-pronuclear (2PN), 3PN and 1PN zygotes. Secondary outcomes were blastulation, cumulative positive b-human chorionic gonadotrophin test and clinical pregnancy rates. Relationships between ejaculatory abstinence and fertilization outcomes, and ejaculatory abstinence and clinical outcomes were evaluated with multivariable analysis, including possible confounders. Results: A positive association was observed between ejaculatory abstinence and semen sample volume (P < 0.001), sperm concentration (P < 0.001) and total motile sperm count (P < 0.001). No association was found between the 1PN zygote rate and ejaculatory abstinence (P = 0.97). Conversely, for each additional day of ejaculatory abstinence, the likelihood of obtaining 2PN zygotes from all inseminated oocytes decreased by 3% [adjusted odds ratio (aOR) 0.97, 95% CI 0.94-0.99], whilst the likelihood of obtaining 3PN zygotes from all inseminated oocytes increased significantly by 14% (aOR 1.14, 95% CI 1.07-1.22). No significant associations were found between ejaculatory abstinence and blastulation, cumulative pregnancy or miscarriage rates. Conclusions: A longer ejaculatory abstinence period significantly decreases the rate of 2PN zygotes, and increases the rate of 3PN zygotes without directly affect blastulation and pregnancy rates.

Abstract Study question Is ejaculatory abstinence (EA) associated with fertilization and blastocyst development in ICSI cycles with embryo culture in time-lapse incubators? Summary answer There is no association between length of EA and fertilization, blastocyst development or morphology. What is known already Semen analysis is pivotal in medically assisted reproduction (MAR), serving as a significant indicator of male partners’ health. The period of EA is a relevant factor that can affect sperm quality. Numerous studies described EA association with clinical outcomes, while its impact on embryological results remains inconclusive. Recent meta-analyses, despite a conflicting literature, highlighted positive effects of shorter abstinence periods. A recent study suggested that prolonged abstinence might reduce fertilization rate in ICSI cycles without time-lapse imaging, thereby reducing usable zygotes’ rate Study design, size, duration Retrospective study including all oocytes (N = 7164) from 1148 ICSI cycles (N = 902 couples) cultured in time-lapse incubators at a single IVF center between January 2020 and December 2022. Only non-donor fresh gametes were included (Mean Maternal age: 38.5±4 years; Paternal Age: 41±5.6 years). The primary embryological outcomes were fertilization rate and type, and blastocyst development per inseminated oocyte and per 2PN-zygote. Secondary outcomes were euploidy, day of blastocyst development and Gardner’s morphology. Participants/materials, setting, methods Semen analysis was conducted according to WHO. All oocytes were cultured up to day7 in EmbryoScope or GERI incubators with continuous media and refresh in day5 (if needed). If requested, PGT-A was performed to assess full-chromosome uniform aneuploidies. Univariate and multivariate logistic regressions were conducted. Possible confounders were assessed among ovarian stimulation, maternal, paternal, sperm, and IVF cycles characteristics. Associations were confirmed with Generalized estimating equations (GEE) to account for repeated measurements among oocytes’ cohort. Main results and the role of chance Logistic regressions and GEE were conducted to assess associations between possible confounders and blastocyst development per inseminated metaphase-II oocyte. Maternal age, sperm concentration, and motility A+B were associated. The same confounders were reported on blastocyst development among 2PN-zygotes. The days of EA (1-8 days) did not show any association with fertilization (p = 0.198) or blastocyst development per metaphase-II oocyte (p = 0.495). No association was reported with abnormal fertilization, neither combining all abnormalities in a single group, nor clustering them as 1PN, 3PN, 3.1PN, and multi-PN. An increasing trend was reported in blastocyst development among 2PN-zygotes according to the length of EA (1-day: 17/37,45.9%; 2-days: 190/424,44.8%; 3-days: 1405/2574,54.6%; 4-day: 746/1410,52.9%; 5-days: 450/827,54.4%; 6-days: 70/133,52.6%; 7-days: 46/101,45.5%; 8-days: 85/162,52.5%), but this was not significant in a multivariate logistic regression (p = 0.887). Length of EA showed no association with euploidy (p = 0.424), nor with day of development (p = 0.966) and Gardner’s inner cell mass (p = 0.204) or trophectoderm (p = 0.428) morphology. Limitations, reasons for caution This study is inherently limited by its retrospective design. The limited number of cycles included was balanced using time-lapse incubators to improve the accuracy of fertilization check and benefit from an undisturbed embryo culture environment. Artificial Intelligence will be implemented to automate developmental timings’ annotation and objectify embryo quality assessment. Wider implications of the findings The length of EA seems not associated with embryological outcomes, adding to the controversy on this topic. Here, we included only ICSI cycles with blastocyst culture conducted in time-lapse to enhance the quality of the evidence. Larger datasets and diverse settings are now required, especially enriched with poor prognosis patients. Trial registration number not applicable

BACKGROUND AND AIM Effective IVF lab management is pivotal. Achieving this requires balancing operator training, monitoring key performance indicators (KPIs), workload, and timings. However, current evidence is contradictory. This study aimed to evaluate the impact of lab management factors, including operators, workload, year (2015 to 2022), retrieval-to-denuding timings, specific sequential oocyte-retrieval of the day, culture media, and incubators, on embryological outcomes in 7986 ICSI cycles conducted by 5204 couples across 2114 working days with ≥1 oocyte-retrieval. METHODS Data on operators and timings were collected automatically using an electronic witnessing system (EWS). Associations with embryological outcomes were analyzed using multivariate linear regressions and generalized estimating equations (GEE), considering repeated measures for couples undergoing multiple retrievals. RESULTS On average, 6.6±4.5 (range:1-32) MII-oocytes were inseminated in 38.5±3.8 (24-48) years-old women, whose partners’ Severe Male Factor (SMF) prevalence was 18.9%.Overall 27.7±15.9 (1-94) procedures were conducted by 8.2±2.4 (3-12) operators per day. Oocyte-retrievals plus ICSI (4.4±2.6 per day, 1-15) represented 7-24% of the daily procedures. These figures increased across the years and were unevenly distributed across the week. The procedures per operator on Fridays, Saturdays and Sundays were 0.6X, 1.4X and 2.4X than the average of 3.6±2.2 (0.1-21). Differences in fertilization-rates appeared among years, days of the week, specific sequential number of oocyte-retrieval, and denuding/ICSI operators. However, the only significant association after adjusting for maternal age and SMF was the time retrieval-to-denuding (unstandardized-B:-1.5%, 95%CI:-2% to -1%,p<0.001). Denudings conducted beyond 3 hours showed fertilization rates >75% that decreased until falling below the clinic average (73%±26%) for denudings beyond 5 hours. Similar trends were observed for blastulation-rates (unstandardized-B:-1.3%,95%CI:-1.9% to -0.6%,p<0.001) that decreased from ≥50% to ≥45% for denudings conducted beyond 3 hours from retrieval. Continuous media performed better than sequential (unstandardized-B:-2.6%,95%CI:-3.9% to -1.2%,p<0.001) and undisturbed incubators than disturbed (unstandardized-B:-1.6%, 95%CI:-2.2% to -0.9%,p<0.001). No association was reported for euploidy-rates among the 5262 PGT-A cycles. CONCLUSIONS These findings suggest that balancing daily/weekly workload - even when substantial - with the number of well-trained and controlled operators can maintain or even improve the overall IVF performance, carefully monitored through lab KPIs. Notably, the time retrieval-to-denuding should not exceed 3-4 hours.

Abstract Study question How many retracted papers are there in the medically assisted reproduction (MAR) literature and, more importantly, what are their particulars? Summary answer Article retraction within MAR literature is increasing and the most common reasons for retraction are errors in data and duplicate publications. What is known already Article retraction accounts for one of the most serious consequences of research misconduct. Articles may be subject to retraction whenever the findings are found to be unreliable, redundant, plagiarised or the authors are found to have performed unethical research or hidden Trial registration number N/A

Abstract Study question Does ejaculatory abstinence period in male affect embryological and pregnancy outcomes following fresh embryo transfers in ICSI cycles? Summary answer Shorter ejaculatory abstinence period is associated with lower triploid zygotes rate per ICSI cycle but it does not affect clinical outcomes after fresh embryo transfers. What is known already Lower sperm quality may negatively impact on fertilisation rate and embryo morphokinetic parameters after ICSI and the effect of the ejaculatory abstinence period before semen collection on seminal parameters and sperm quality has been widely reported. However, the impact of ejaculatory abstinence on clinical outcomes is still controversial. WHO (World Health Organization) guideline recommended that abstinence period should be 2–7 days. Even so, there are no larger prospective trials determining the optimal timing for ejaculatory abstinence period for infertile couples. Study design, size, duration This is a single center retrospective observational study of 3,353 fresh cycles from January 2017 to December 2020. Semen analysis was done according to the WHO criteria. Exclusion criteria for this study were frozen gametes and cycles with no retrieved oocytes. Primary outcomes were fertilization rate and triploid zygotes rate. Secondary outcomes were blastulation rate, ongoing pregnancy rate and live birth rate per fresh embryo transfer. Participants/materials, setting, methods The correlation between ejaculatory abstinence and continuous outcomes was evaluated by Spearman’s correlation analysis in order to detect potential non-linear associations. Generalized linear model and logistic regression were used, respectively for continuous and binary outcomes, in order to adjust for confounders such as female age, male age, number of retrieved oocytes, percentage of mature oocytes, infertility causes, seminal volume, sperm concentration and total progressive sperm motility. A p value <0.05 was considered significant. Main results and the role of chance The male mean age was 40.3±5.5 and mean duration of abstinence was 2.9±1.7 days. The mean age of female patients was 38.2±4.0. Higher ejaculatory abstinence period was associated with a higher sperm concentration (Spearman p = 3.1x10–6) but not with a higher total sperm progressive motility. Even so, no significant correlation with EA were observed when considering fertilization rate, blastulation rate, ongoing pregnancy and live birth rate per transfer in analyzed cycles. Triploid zygote rate was positively associated with a higher ejaculatory abstinence period. For the ejaculatory abstinence period of 1 day (n = 64), 2 days (n = 1523), 3 days (n = 1032), 4 days (n = 408), 5 days (n = 174), 6 days (n = 47) and ≥7 days (n = 105) the mean triploid rate was 2.4%, 2.4%, 2.5%, 4.1%, 3.6%, 5.4% and 4.3%, respectively (Spearman p = 9x10–3). Triploid zygote rate was independent of semen volume, concentration and total progressive motility. Limitations, reasons for caution This is a large observational study with a retrospective data collection. Despite our methodological approach, the presence of biases related to retrospective design can not be excluded and it may be a reason for caution. Wider implications of the findings: Our results demonstrate that ejaculatory abstinence period do not affect blastulation, ongoing pregnancy and live birth rates. The current findings discourage an abstinence time longer than 3 days due to its association with a higher abnormal fertilization rate. Trial registration number Not applicable