Abstract
Various ovulation markers in natural cycle (ultrasound measurement of follicular diameter, E2, progesterone, and LH assays) have been studied in 18 women. The patients were divided into two groups. Group 1: women who became pregnant during the same cycle; group 2: women who showed evidence of follicular growth, E2 and a LH midcycle rise, but low P levels in the luteal phase. A weaker increase in these parameters was found in group 2, especially the LH rise. Moreover, an asynchronicity between the en-docrinological and morphological events has been observed in the suboptimal cycles. These findings suggest a process of follicular atresia at the end of the maturation phase, as is commonly found in otherwise normal women.