Progesterone is the most important hormone in a group of steroid hormones known as progestogens. This hormone plays a significant role during your pregnancy by affecting your uterus, amniotic fluid, and your immune system. Overall, progesterone is involved in maintaining your pregnancy and preventing preterm birth. As a supplement, progesterone is used during pregnancy primarily for recurrent miscarriage and to prevent preterm labor. There is a lot of research on the use of progesterone, and this episode dives into the role progesterone plays, testing your levels, supplementing, and using progesterone to prevent miscarriage and preterm birth.