Urinary follicle-stimulating hormone peak as a biomarker for estimating the day of ovulation.

OBJECTIVE

To evaluate urinary follicle-stimulating hormone (FSH) as a biomarker for the day of ovulation.

DESIGN

Prospective observational study.

SETTING

Clinical research center.

PATIENT(S): Thirteen women were monitored with measurements of serum and urinary hormones and ovarian ultrasonography during 20 menstrual cycles. Data on urinary hormones and ultrasound evaluations from a total of 65 menstrual cycles from 42 women were analyzed.

INTERVENTION(S): Blood and/or urine samples were collected daily. Daily transvaginal ultrasonography was used to detect follicular collapse.

MAIN OUTCOME MEASURE(S): LH, FSH, and E(2) were measured in serum. FSH, estrone conjugates (E1C), and pregnanediol-3-glucuronide (PdG) were analyzed in urine. The day of luteal transition (DLT) was calculated using two algorithms.

RESULT(S): In 20 cycles, the urinary FSH peak was closer to the day of follicular collapse (-0.85 days) than was the peak day of serum E(2) and the day of luteal transition, as calculated by one algorithm. The FSH peak was not closer to the day of follicular collapse than the peak values of urinary LH, serum FSH, or the day of luteal transition as calculated by a second algorithm. The most consistent correspondence between a hormone peak and ovulation was for serum E(2), serum FSH, serum LH, and urinary FSH. In 65 cycles for which urinary hormone data and ultrasound evaluations were available, the urinary FSH peak occurred within 1 day of follicular collapse in 97% of cycles.

CONCLUSION(S): Urinary FSH is a useful biomarker for estimating the day of ovulation in population-based studies.