Daily variation in plasma levels of progesterone and estradiol throughout the menstrual cycle

Abstract

Daily concentrations of progesterone and estradiol were measured throughout the menstrual cycle in 6 apparently healthy, regularly menstruating women. Four women showed typical “ovulatory” patterns; the fifth subject had an anovulatory cycle, while the remaining woman became pregnant and subsequently aborted spontaneously during the fourth month. During the 4 ovulatory cycles, plasma progesterone levels rose sharply following the preovulatory estradiol peak. The premenstrual phase was characterized by a simultaneous decline in plasma levels of both progesterone and estradiol. In the woman who became pregnant during the cycle under study, the early surge in plasma progesterone was not accompanied by a similar rise in plasma estradiol. The anovulatory cycle was associated with a delayed peak in estradiol and absence of a significant elevation in plasma levels of progesterone during the second half of the cycle. The significance of these hormone patterns is discussed in relation to the underlying ovarian physiology.