Peak coital rate coincides with onset of luteinizing hormone surge.

Twenty-five married women who were not using contraceptives provided daily urine specimens and coital reports for at least 90 days. The authors used urinary luteinizing hormone (LH) as a hormonal marker to determine ovulatory phase, onset of LH surge day, and LH peak day. Coital rate was elevated during the ovulatory phase of the menstrual cycle. Peak coital rate (0.72) occurred on onset of LH surge day, and was significantly greater (P less than 0.05) than the mean rate (0.44 +/- 0.06) across the entire menstrual cycle. The authors discuss possible social and hormonal mechanisms that might underlie an ovulatory peak in coitus, as well as the relevance of their findings to current models of fecundability.