Impact of trigger-day serum luteinizing hormone levels on embryo quality and pregnancy outcomes in overweight and obese women undergoing GnRH antagonist protocols: a retrospective cohort study

Introduction: ) 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: 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.