Allylestrenol

White or nearly white crystalline powder, molecular weight 300.49, purity can enhance the activity of chorionic villi, promote the secretion of endogenous progesterone and hCG, promote the normalization of placental function; increase the concentration and activity of oxytocin, reduce the level of oxytocin; increase the excitation threshold of uterus, and antagonize the stimulation effect of prostaglandin on uterus. There was no estrogen and androgen activity. It is suitable for threatened abortion, habitual abortion and threatened premature delivery.