RESUMEN
OBJECTIVE: To describe FSH profile variants. DESIGN: Observational study. SETTING: Multicenter collaborative study. PATIENT(S): A total of 107 women. INTERVENTION(S): Women collected daily first morning urine and underwent serial ovarian ultrasound. MAIN OUTCOME MEASURE(S) FSH RESULT(S): The individual FSH cyclic profiles demonstrated a significant departure from the currently accepted model. A decline in FSH levels at the end of the follicular phase was observed in only 42% of cycles. The absence of this decline was significantly associated with a shorter luteal phase and higher pregnanediol-3α-glucuronide, FSH, and LH levels at the time of ovulation. In 34% of the cycles, significant FSH variability was observed throughout the follicular phase; this variability was associated with higher body mass index and lower overall FSH and LH levels throughout the cycle. The FSH peak occurs on average 2 hours before ovulation. The FSH peak duration was shorter than the LH peak. CONCLUSION(S): These results suggest that average FSH profiles may not reflect the more complex dynamics of daily hormonal variations in the menstrual cycle. It is possible that discrepancies between the average normal FSH profile and the individual day-to-day variants can be used to detect abnormalities.