Hypersensitivity. Ovarian, breast, uterine, pituitary or hypothalamic tumours. Abnormal vag bleeding w/o known diagnosed cause. Primary ovarian failure. Ovarian cysts or enlarged ovaries. History of ovarian hyperstimulation syndrome (OHSS); previous COS cycle resulted in >30 follicles ≥11 mm measured by ultrasound exam; basal antral follicle count >20; polycystic ovarian syndrome. Uterine fibroid tumours & reproductive organ malformations incompatible w/ pregnancy. Pregnancy.