Incidence of ovulatory cycles in women approaching the menopause

Abstract

Summary Urine was collected at weekly intervals at weekly intervals for three or more months from 139 menstruant women aged 40–55 years. Menstrual cycles were classed as ovulatory if the 24-hr pregnanediol output was > 5 μmol on a single occasion, or if the total excreted on 2 days 1 week apart was > 7 μmol. Of the 81 women who reported no change in menstrual frequency, 95% ovulated in every cycle. Only 34% of the 53 with a recent history of oligomenorrhoea ovulated without fail. Ovalation occurred in 93% of all 21–35-day menstrual cycles, in 55% of 36–50-day cycles, in 40% of 51–75-day cycles and in 17% of those lasting > 76 days. Pregnanediol increases suggestive of ovulation and followed by menstruation were observed on 31 occasions after amenorrhoea of from 2 to 6 months' duration.