Allylestrenol

Allylestrenol is a steroidal progestin of the 19-nortestosterone and 17α-allyltestosterone groups that is used to prevent threatened miscarriage, recurrent pregnancy loss and premature labor.It has also been studied as a treatment for benign prostatic hyperplasia in men, with encouraging results. Although it is less potent as a progestogen relative to many other 19-nortestosterone derivatives,allylestrenol is said to be virtually devoid of androgenic, estrogenic, or glucocorticoid activity, and hence, unlike virtually all other 19-nortestosterone derivatives, appears to be a pure progestogen with similar effects to those of progesterone.As it is lacking in a keto group at the C3 position, allylestrenol is thought to be a prodrug into 17α-allyl-19-nortestosterone (or 17α-allylnandrolone)

Allylestrenol is a progestogen structurally related to progesterone that has been given in threatened and recurrent miscarriage, and to prevent premature labour. However, with the exception of proven progesterone deficiency, such use is no longer recommended. In threatened miscarriage in progesterone-deficient women a suggested dose is 5 mg three times daily by mouth for 5 to 7 days.