Preovulatory serum gonadotropin levels in hMG stimulated menstrual cycles in pregnant and nonpregnant patients.

In a group of patients undergoing in vitro fertilization, 10 pregnant and 10 nonpregnant, cycles were analysed in retrospect in relation to gonadotropin and steroid hormones. All patients were similar in terms of age, body surface area and initial stimulation protocol. The increase in follicles stimulating hormone (FSH) was significantly higher in the pregnant group through cycle day 8 as compared with cycle day 3 before stimulation. A significant increase in the nonpregnant group was never detectable; the mean FSH levels rather decreased to the baseline value during stimulation after a slight nonsignificant increase. The levels of luteinizing hormone (LH) decreased significantly in pregnant and nonpregnant patients during stimulation. No significant difference in the FSH/LH ratio between the pregnant and nonpregnant group was encountered. Although the mean serum estrogen in the follicular phase and the serum estrogen and progesteron values in the luteal phase were higher in the pregnant patients, no statistically significant difference between groups could be demonstrated, until luteal day 11. It is believed from this study, that a 15-20% increase in serum FSH levels over baseline during the early and mid follicular phase is required for adequate follicular development and steroidogenesis. The determination of serum gonadotropins in the follicular phase in patients who failed to conceive, might reveal differences, which can account for failures in hMG induced cycles.