Basal FSH as a predictor of good-quality embryo yield and cumulative reproductive outcomes in young women with low AMH undergoing IVF/ICSI

To assess IVF/ICSI outcomes and their determinants in young patients with low basal AMH stratified by basal FSH levels. This retrospective cohort study included 70,644 IVF/ICSI cycles conducted at a tertiary reproductive center between 2017 and 2022. After 1:2 propensity score matching for age and AMH, women aged 20–39 years with low AMH (< 1.1 ng/mL) were categorized into two extreme basal FSH phenotypes: low FSH (< 5 mIU/mL, n =298) an high FSH (> 25 mIU/mL, n =149). Among young women with low AMH, those with low basal FSH exhibited higher BMI and AFC, as well as longer stimulation duration and higher total Gn doses (all P < 0.01). They yielded more retrieved oocytes, fertilized embryos, and good-quality embryos than those in the high-FSH group (all P < 0.01). The cumulative clinical pregnancy and live birth rates were significantly higher in the low-FSH group (19.80% vs. 8.05%, P = 0.001; 16.78% vs. 6.04%, P = 0.002). In multivariable logistic regression, high FSH was associated with lower odds of cumulative clinical pregnancy and cumulative live birth. After further inclusion of the number of good-quality embryos in the model, these associations were attenuated but remained statistically significant, suggesting that differences in good-quality embryo yield may contribute to the association between basal FSH and cumulative reproductive outcomes. Among young women with low AMH, patients with low basal FSH showed better ovarian response, higher good-quality embryo yield, and more favorable cumulative pregnancy outcomes. Elevated basal FSH may help identify a subgroup of young women with low AMH who have poorer embryo yield and cumulative reproductive outcomes. These findings suggest that favorable outcomes remain achievable in low AMH patients with low basal FSH level.