Contraceptive pills generally contain the hormones estrogen and progesterone. If taken daily from the 4th day after menses the abnormal elevation of these hormones acts upon the hypophysis- hypothalamus endocrine axis inhibiting the FSH and LH secretions. Since these hormones then do not reach their normal high levels during the menstrual cycle ovulation does not occur ( Treatment with contraceptive pills must be initiated under medical supervision.)