Xenoestrogen
Xenoestrogens are clinically significant because they can mimic the effects of endogenous estrogen and thus have been implicated in precocious puberty and other disorders of the reproductive system.
Norethisterone
Norethisterone is used as a hormonal contraceptive in combination with an estrogen – usually ethinylestradiol (EE) – in combined oral contraceptive pills and alone in progestogen-only pills. Norethisterone has also been shown to be effective in inhibiting leutinizing hormone and follicle-stimulating hormone secretion in men as well. Without these hormones, mature sperm cannot survive in the testes. This means that norethisterone could also be an effective male hormonal contraceptive. Aside from its use as a contraceptive, norethisterone can be used to treat premenstrual syndrome, dysmenorrhea, menorrhagia, irregular menstruation, menopausal symptoms (in combination with estrogen), or to postpone a period. It is also commonly used to help prevent uterine hemorrhage in complicated non-surgical or pre-surgical gynecologic cases and in treating non responsive cyclical mastalgia.