The secretion of progesterone during the periovulatory period in women with certified ovulation.

A pre-LH peak rise of progesterone in peripheral blood has been found in 13 normal cycling women whose ovulation was confirmed by biopsy of the corpus luteum through serial determination of progesterone and LH performed every 8 h during the periovulatory period. The progesterone rise began as an average 22 h (16-40 h) prior to the LH peak. The maximal preovulatory rise took place 9.6 h (0-24 h) before the LH zenith, remaining low for approximately 17 h when an abrupt rise of progesterone took place. The progesterone peak was detected in the morning samples in 11 of 13 patients studied. The progesterone rise was always followed by an LH peak and the highest peak of progesterone was trailed by the highest LH peak in all the patients except one.