Danping Li, Wenhan Ju, Xina Zhen, Demin Lv, Wenli Yang, Shan Xiang, Fangting Duan
Introduction Luteinizing hormone (LH) is critical for follicular development and IVF pregnancy outcomes, but evidence linking trigger-day serum LH levels to IVF-ET outcomes in overweight patients is scarce. This study investigated the impact of trigger-day LH levels on IVF-ET outcomes in overweight and obese women (BMI ≥ 25 kg/m 2 ) undergoing flexible GnRH antagonist controlled ovarian stimulation (COS). Methods Clinical data from 1,135 overweight and obese women (first IVF/ICSI-ET cycle, July 2023–July 2024) were retrospectively analyzed. Patients were stratified into three groups based on the 25th (P25) and 75th (P75) percentiles of the trigger-day LH distribution: Group 1 (< P25, LH < 1.45 IU/L, n=272), Group 2 (P25–P75, 1.45 IU/L ≤ LH ≤ 4.19 IU/L, n=580), and Group 3 (> P75, LH > 4.19 IU/L, n=283). Ovarian response, embryo quality, and pregnancy outcomes were compared; binary logistic regression evaluated LH-pregnancy associations, with subgroup analyses by transfer type, PCOS status, and BMI category. Results Group 1 had significantly more follicles ≥14 mm, retrieved/mature/fertilized oocytes, and high-quality embryos than Groups 2 and 3 (all P < 0.05), with LH levels negatively correlated with these indicators (all P < 0.05). No significant differences in clinical pregnancy or live birth rates after the first embryo transfer were observed among groups (all P > 0.05), consistent across subgroups. After adjusting for confounders including embryo parameters, trigger-day LH grouping was not independently associated with clinical pregnancy rates of the first transfer (Group 2: aOR=0.945, 95%CI 0.649–1.376, P = 0.767; Group 3: aOR=1.130, 95%CI 0.820–1.557, P = 0.457). Conclusion Elevated trigger-day LH levels correlate with poorer ovarian response and embryo quality in overweight and obese women on GnRH antagonist protocol, but not with pregnancy outcomes, nor are they an independent predictor of IVF success.