Preconceptional thyroid-stimulating hormone affects antral follicle count rather than pregnancy outcomes in patients with first in vitro fertilization/intracytoplasmic sperm injection cycle

Objective: To study the effects of preconceptional thyroid-stimulating hormone (TSH) levels on antral follicle count (AFC) and pregnancy outcomes in a first in vitro fertilization (IVF)/intracytoplasmic sperm injection (ICSI) cycle. Methods: A retrospective cohort study was conducted to explore the effects of preconceptional TSH levels on AFC and pregnancy outcomes in 1340 patients. The patients were divided into three groups: group 1, 0.55≤ TSH <2.5 uIU/mL ( n = 868); group 2, 2.5≤ TSH <4.0 uIU/mL ( n = 334); and group 3, TSH ≥4.0 uIU/mL ( n = 138). Results: There were significant differences in AFC ( P = 0.002), number of zygotes ( P = 0.008), and fertilization rate ( P = 0.015) among the three groups. Among the three groups, there were no obvious differences in live birth ( P = 0.559), high-quality embryo ( P = 0.108), or clinical pregnancy ( P = 0.939) rates. Binary logistics regression analysis showed that TSH correlated with AFC when TSH was ≥4 uIU/mL ( P = 0.033); however, TSH levels had no effect on live birth or clinical pregnancy rate. Conclusions: Although the preconceptional TSH level negatively related with AFC, number of zygotes, and fertility rate, especially when TSH was >4 uIU/mL, TSH was not an independent factor on the live birth rate among fertile women undergoing their first IVF/ICSI-embryo transfer treatment. The effect of TSH levels on couples undergoing assisted reproductive technology requires further investigation.