Do women have worse pregnancy and neonatal outcomes of IVF/ICSI–fresh embryo transfer (ET) after conservative treatment of atypical hyperplasia (AH)? AH has no impact on live birth but is associated with increased risks of pregnancy loss and preterm delivery (PTD). AH is a precancerous lesion of endometrial cancer. Several recognized AH risk factors include nulliparity, increased body mass index, ovulation disorders, diabetes mellitus, and others. As such, patients are suggested to attempt conception upon achieving AH regression. Recently, successful pregnancies with IVF/ICSI have been increasingly reported. Forty-two patients with AH regression and 18 700 women with no evidence of endometrial abnormality, who underwent their first autologous oocytes’ retrieval and fresh ET cycles of IVF/ICSI in the Center for Reproductive Medicine, Shandong University, from May 2008 to July 2021, were retrospectively enrolled. First, 42 AH patients were propensity score matched with control women (n = 168) at a 1:4 ratio. Reproductive outcomes and maternal/neonatal complications were compared between the matched pairs. Binary logistic regression analyses were conducted to assess odds ratios (ORs) of AH for live birth, pregnancy loss, and PTD from AH women and all 18 700 eligible controls. Patients with AH achieved a numerically lower live birth rate (LBR) as compared to the matched controls, but without significant difference (26% versus 37%, P = 0.192). However, compared with the matched controls, AH patients showed significantly higher rates of pregnancy loss (52% versus 21%, P = 0.003) and PTD (45% versus 16%, P = 0.041). Further analyses revealed a statistically significantly increased rate of late pregnancy loss (17% versus 3%, P = 0.023), but not early miscarriage (35% versus 18%, P = 0.086), in the AH group. Furthermore, after correcting for potential confounders, the likelihood of a live birth in AH patients narrowly failed to be statistically significantly different from controls (adjusted OR [aOR]: 0.51, 95% CI: 0.25–1.04, P = 0.064). Nonetheless, the logistic regression reconfirmed that AH was an independent risk factor for pregnancy loss (aOR: 3.62, 95% CI: 1.55–8.46, P = 0.003), late pregnancy loss (aOR: 9.33, 95% CI: 3.00–29.02, P < 0.001), and PTD (aOR: 5.70, 95% CI: 1.45–22.38, P = 0.013). Selection bias was an inherent drawback of this study. First, because of the low AH prevalence among women receiving IVF/ICSI treatment, and consequently, limited sample size, the relationship between AH with LBR and adverse complications might be concealed and underestimated. Hence, the results should be interpreted cautiously. Similarly, the impacts of diverse clinical features of AH patients on the pregnancy outcomes need further studies in a larger population. Second, although most data used in this study were obtained by reviewing the medical records, missing data did exist and so did the recall bias. Third, although the propensity score matching and multivariable logistic models were performed collectively in order to minimize potential confounders between AH and controls, the intrinsic disadvantages of the retrospective nature of this study could not be avoided completely, and additional confirmation bias might be induced with reduplication of statistical analyses. Our results highlight the necessity of adequate counseling and intensive pregnancy monitoring for AH individuals and their families. This work was supported by grants from the National Key Research & Developmental Program of China (2022YFC2703800), the Natural Science Foundation of Shandong Province (ZR2022MH009), and Projects of Medical and Health Technology Development Program in Shandong Province (202005010520, 202005010523). There are no conflicts of interest to declare. N/A.

Purpose: To identify the specific risk factors associated with unexplained infertility (UI) among infertile couples. Methods: We conducted a retrospective cohort study analyzing UI risk factors, focusing on 5465 infertile couples who completed their first full in vitro fertilization/intracytoplasmic sperm injection (IVF/ICSI) cycle out of a total cohort of 62201 infertile couples. Results: Among 5465 UI couples, 3400 achieved a live birth (cumulative live birth rate = 62.2%). Multivariate logistic regression indicated the key negative predictors included: female age ≥ 35 years (odds ratio [OR]: 0.63; 95% confidence interval [CI]: 0.51–0.78; p < 0.001), male age (OR: 0.98; 95% CI: 0.96–0.99; p = 0.015), Female body mass index ≥ 27.5 kg/m ² (OR: 0.78; 95% CI: 0.62–0.97; p = 0.028), low anti‐Müllerian hormone (AMH) (AMH < 1.2 ng/mL) (OR: 0.64; 95% CI: 0.52–0.77; p < 0.001), and a mid‐range endometrial thickness (EMT) (EMT 0.7–1.0 cm) (OR: 0.77; 95% CI: 0.66–0.89; p < 0.001). A higher number of retrieved oocytes positively correlated with cumulative live birth (CLB) (OR: 1.02; 95% CI: 1.01–1.04; p = 0.039). Conclusion: The prevalence of UI was 8.8% in our population, with 62.2% achieving CLB after one complete IVF/ICSI cycle. Female age and ovarian reserve indicators emerged as the main factors influencing oocyte yield, embryo acquisition, and CLB outcomes in UI patients.