Follicle-stimulating hormone levels on cycle day 3 are predictive of in vitro fertilization outcome

Cycle day 3 basal levels of follicule-stimulating hormone (FSH), luteinizing hormone (LH), and estradiol (E₂) were measured in 441 patients in 758 consecutive cycles to determine their predictive value for stimulation quality and pregnancy rates in in vitro fertilization (IVF). Patients with low basal FSH levels (<15 mIU/ml) had higher pregnancy rates per attempt than those with moderate levels (15 to 24.9 mIU/ml), both of which were higher than those with high FSH levels (>25 mIU/ml). Basal LH and E₂ values did not improve the predictive value beyond that provided by FSH. Ongoing pregnancy rates per attempt in the low, moderate, and high FSH groups were 17.0%, 9.3%, and 3.6%, respectively (P < 0.01). The three groups differed significantly in the percentage of patients having two ovaries, the mean number of follicles aspirated per retrieval, the mean number of preovulatory oocytes obtained, and peak E₂ values (P < 0.01). Cycle day 3 FSH levels are predictive of pregnancy outcome and stimulation characteristics in IVF, and may be useful in counseling patients.