Does anovulation exist in eumenorrheic women?

OBJECTIVE: To determine whether anovulation exists in normally menstruating women. METHODS: In a database of 550 consecutive couples seeking pregnancy, results of the midluteal serum progesterone level analysis planned for 7 days before the onset of the next menses were examined in women with predictable cycles shorter than 35 days. RESULTS: Of the 550 couples seeking pregnancy, 410 of the female partners (74.5%) were eumenorrheic. Fifteen of these women (3.7%) had apparently anovulatory cycles with a progesterone lower than the normal ovulatory value of 15 nmol/L. Further examination showed that four of the 15 women (26.7%) had an isolated prolonged cycle, whereas an additional four (26.7%) failed to have their sample taken at an appropriate time. One (6.7%) had a low progesterone level that was normal in the subsequent cycle. Two patients (13.3%) were older than 40, both having elevated early follicular follicle-stimulating hormone levels. One patient (6.7%) conceived in the following menstrual cycle without further evaluation. The three remaining women (20%) showed consistently apparently anovulatory cycles. However, the levels were exclusively above the follicular range. CONCLUSION: Our findings cast doubt on the concept of anovulatory cycles in eumenorrheic women and suggest that further examination of the lower level of ovulatory progesterone may indeed be necessary.