Evaluation of the preovulatory rise of follicle stimulating hormone and progesterone in normally ovulating women of reproductive age.

Sixteen normally ovulating women of reproductive age were evaluated to determine the extent of the preovulatory FSH and progesterone rise in association with the LH surge. Highly significant differences were demonstrated between the baseline and peak preovulatory levels of both FSH and progesterone (P less than .0005). These significant peak ovulatory differences of FSH and progesterone were associated with a 2.5-fold rise (mean difference of 9.06 mIU/mL) of FSH and a 3.0-fold rise (mean difference of 1.94 ng/mL) of progesterone. These small, yet very significant, preovulatory increments of FSH and progesterone are important in the ovulatory process and the formation of an adequate corpus luteum.