Abstract:Objective: To investigate the effect of low levels of luteinizing hormone (LH) on the cumulative live birth rate (CLBR) during ovarian hyperstimulation in GnRH antagonist protocol. Methods: The data of oocytes retrieval cycle of 693 patients in our center who received GnRH antagonist protocol and underwent in vitro fertilization and embryo transfer for the first time were retrospectively analyzed. The lowest LH level≤0.8IU/L in follicular phase was set as group A, and the lowest LH level>0.8IU/L in follicular phase was set as group B. The general clinical data, laboratory indicators and pregnancy outcomes of the two groups were analyzed and compared. Results: The levels of basic FSH, basic LH and LH on human chorionic gonadotropin (HCG) injection day in group A were significantly lower than those in group B (P<0.05).Duration of gonadotropin (Gn), estradiol (E2) level and progesterone (P) level on HCG injection day, number of retrieved oocytes and number of transferable embryos in Group A were significantly higher than those in group B (P<0.05).However, there was no significant difference in CLBR between the two groups (P>0.05). The frequency of serum LH≤0.8 IU/L has no significant influence on the CLBR. After adjusting for confounding factors, multivariate logistic regression analysis showed that the lowest LH level at follicular phase had no influence on CLBR, and the number of retrieved oocytes was an independent predictor of CLBR. Conclusion: Low LH in follicular phase can predict more retrieved oocytes ,but it has no influence on cumulative live birth rate.