Allylestrenol: three years of experience with Gestanon in threatened abortion and premature labor.

Allylestrenol was used to treat 375 women with threatened pregnancies. Results show that this drug is capable of maintaining pregnancy in a large series of ambulant patients and is safe for both mother and child. Allylestrenol does not maintain pregnancy if placental dysfunction is present, however. Newborns whose mothers are treated with allylestrenol have slightly higher birth weights than controls. The possible role of allylestrenol in this process is discussed. At high doses, allylestrenol effectively stops premature labor, suggesting a selective action on the myometrium.