Elevated baseline LH/FSH ratio is associated with poor ovulatory response but better clinical pregnancy and live birth in Chinese women with PCOS after ovulation induction

Background: What is the association between elevated baseline LH/FSH ratio and reproductive outcomes, especially ovulatory response, among Chinese women with polycystic ovary syndrome (PCOS) after ovulation induction. Methods: This was a secondary analysis of a multicenter randomized trial in 1000 women with PCOS from 21 sites (27 hospitals) in Mainland China. LH and FSH levels before ovulation induction and the main outcomes including ovulation, biochemical pregnancy, clinical pregnancy, miscarriage, and live birth were measured. A linear regression model, logistic regression models and Cox proportional hazard regression model were used to estimate the association between LH/FSH ratios and reproductive outcomes in PCOS. Results: LH/FSH ratio was significantly associated with age, body mass index (BMI), total testosterone (TT), estradiol (E2), free testosterone (FT), and antimullerian hormone (AMH). Anovulatory women had significantly higher LH/FSH ratio than ovulatory women (P = 0.003), especially in women with young age (P = 0.023), high BMI (P = 0.002), low E2 (P = 0.002), FT (P = 0.010), TT (P < 0.001) and AMH(P = 0.032). Women with elevated LH/FSH ratio were associated with lower ovulation (LH/FSH≥1 OR = 0.42, 95% CI, 0.26–0.68; LH/FSH≥2 OR = 0.32, 95% CI, 0.20–0.54; LH/FSH≥3 OR = 0.40, 95% CI 0.21–0.74) when compared with LH/FSH<1. The association was held after adjustment for treatment with or without the confounding factors. Although no association between LH/FSH ratio and biochemical pregnancy, women with 1 ≤ LH/FSH<2 were associated with higher clinical pregnancy (OR = 1.71; 95% CI, 1.09–2.67) and live birth (OR = 1.73; 95% CI, 1.09–2.75) compared to women with LH/FSH<1. Women with 2 ≤ LH/FSH<3 were associated with lower miscarriage rate (OR = 0.38; 95% CI, 0.16–0.93). Conclusions: Elevated baseline LH/FSH ratio in women with PCOS was associated with poor ovulatory response, but women were more likely to achieve clinical pregnancy and live birth than women with normal LH/FSH. It suggests LH and FSH in women with PCOS may play a role in successful pregnancy despite of negative impact in ovulation.