Objective: To evaluate hormonal profiles of normal menstrual cycles. Design: Prospective, descriptive study of a case series. Setting: University-based natural family planning center. Patient(s): Twenty-five natural family planning users for three or more cycles (n = 78). These women were healthy, contraception-free, parous, with regular ovulatory cycles. Intervention(s): Immunoassays for estrone glucuronide, LH, and pregnanediol glucuronide were done in daily timed and measured samples of early morning urine. Main Outcome Measure(s): Estrone glucuronide, LH, and pregranediol glucuronide levels were measured during the menstrual cycle, Result(s): All cycles showed an ovulatory pattern configuring classic hormonal mean curves. Most (77%) differed from the mean curve pattern. All had estrone glucuronide peaks. LH peaks, and pregnanediol glucuronide increases. Estrone glucuronide and LH peaks were not always clear; some lasted more than I day (long peak: estrone glucuronide 19%, LH 9%) or fluctuated (double peak: estrone glucuronide 4%, LH 6%, small LH peak: 19%). There were also prepeak estrone glucuronide surges, and pre- and postpeak LH surges. Pregnanediol glucuronide increased more clearly (6% fluctuated I day). Some women had repeated cycles with long estrone glucuronide peaks (16%) and fluctuations in LH surge (44%). Conclusion(s): Normal menstrual cycle hormonal profiles generally differ from mean curves, which are usually considered standard, (C) 2002 by American Society for Reproductive Medicine.