As Melatonin regulates the sleep wake cycle it has implications in menstrual irregularities as well. Shift workers whose sleep wake cycle is disturbed experience menorrhagia like heavy and longer bleeding periods. in very high doses, when combined with progesterone, melatonin has the ability to suppress ovulation in humans, possibly by interfering with LH release. As mature ovarian follicles have higher concentrations of follicular fluid melatonin than smaller immature follicles it may imply a role for melatonin in oocyte maturation. It has role in foetal brain growth in pregnancy by increasing placental function.