Vaginal organic acids and hormonal changes in the menstrual cycle.

Twenty-seven women not using oral contraceptives (OCs) and 22 women using OCs were studied during one complete menstrual cycle. Twenty-four-hour vaginal secretions, collected on alternate days by a tampon method, were analyzed for acetic and other short-chain aliphatic acids and for lactic acid. Daily blood samples were analyzed for estrogens, progesterone (P), and luteinizing hormone (LH). No difference was found between OC users and nonusers in either amount or variability of vaginal aliphatic acids throughout the menstrual cycle. Aliphatic acids did not correlate with estrogen of P levels. A significant positive correlation was found between vaginal lactic acid and blood estrogens in those subjects not using OCs.