<p>Allylestrenol is a synthetic progesterone derivative that is used to treat threatened pregnancies. It can stop occurring premature labor and can help women give birth to a healthy newborn. It stimulates the secretory phase in myometrium, creates conditions for development of fertilized ovum. It has a tocolytic effect; reduces sensitivity of myometrium to oxytocin. It stimulates the development of acinus of mammary glands, secretory activity of trophoblasts, and development of aldosterone by adrenal glands. Allylestrenol also has a selection of &amp;beta;-adrenergic effect. In this way, it stimulates the synthesis of the body&#39;s placental progesterone, therefore increasing the secretion of placental hormones.</p>