Occurrence of a spontaneous luteinizing hormone surge in superovulated cycles--predictive value of serum progesterone.

A preovulatory increase in serum progesterone (P) precedes the occurrence of an endogenous luteinizing hormone (LH) surge in a majority of women. This study evaluates whether a single daily measurement of serum P could reliably identify a spontaneous LH surge in women undergoing controlled ovarian hyperstimulation. Eighty-four infertile women received either clomiphene citrate and human menopausal gonadotropin (hMG), or hMG alone. Serum P levels were increased significantly the morning of the day of an endogenous LH surge (P less than 0.01). A 2-fold rise in the serum P levels was associated with a predictability of 64.4% of a LH surge; however, a 4-fold increase in serum P could accurately predict a spontaneous endogenous LH discharge in 93.3% (P less than 0.001) of cases.