Follicular development during late human pregnancy.

In contrast to the accepted view of ovarian quiescence during pregnancy, the ovaries of preparturient women are covered with a dense population of small superficial follicles. In this study we have measured the follicular size and status of the oocytes and cumulus oophorus in 298 follicles from the ovaries of 30 women. The samples were taken at cesarean section and were examined with Nomarski differential interference microscopy. No oocyte was recovered from 50% of the follicles; 79% of the recovered oocytes and 78% of their cumuli were degenerative. Degeneration was correlated with appearance of phagocytes in the follicular fluid. These findings suggest that the endocrine status of gestation does not prevent early follicular development, but induces premature atresia.