ABSTRACT
OBJECTIVE: Indices of ovarian function and potential fertility have been studied in fully lactating women from the sixth week post-partum to the start of the second menstrual period. PATIENTS: Thirty-four women entered the study and 17 (50%) continued until the first menses. Of these, 16 continued until the second menses. The median time from delivery to day 1 of the first menses was 202 days (range, 85 to 668 days). METHODS: The concentrations of estrone glucuronide (EG) and pregnanediol glucuronide in daily samples of early morning urine were measured by time-resolved fluoroimmunoassay and LH by an immunoradiometric assay. Algorithms were used retrospectively to determine the rise and peak days of all three metabolites. RESULTS: Three cycles were studied relative to day 1 of first menses: (1) premenstrual (days -60 to -31), (2) menstrual (days -30 to -1), and (3) postmenstrual (days 1 to 56). Follicular development occurred in 53%, 100% and 100% of the dated cycles respectively. A peak of LH occurred in 6%, 75% and 80% of cycles, respectively. A period of potential fertility occurred in 11/17 (65%) and 13/16 (81%) of cycles (2) and (3), respectively. The proportion of potentially fertile cycles was higher after the first menses, and after 6 months had elapsed postpartum. CONCLUSION: A test based on the measurement of EG and used prospectively predicted 13/15 (85%) of the periods of potential fertility during the postmenstrual cycle.
