Melatonin and melatonin-progestin combinations alter pituitary-ovarian function in women and can inhibit ovulation.

Although melatonin (MEL) controls seasonal reproductive cyclicity in some mammalian species, its role in women is controversial. In this study data are presented related to the influence of MEL or MEL-progestin combinations on the pituitary-ovarian axis and ovulation in 32 women. MEL was administered in a dosage of 300 mg to 12 women for 4 months [to 8 women daily (days 1-30) and to 4 women on days 5-17 of the cycle].