Information about prontogest suppositories for pregnancy stabilization. prontogest ampoules or suppositories are a medication used to replace a deficiency in the hormone progesterone in women, which is naturally secreted. However, in some cases, a deficiency in secretion occurs, which leads to miscarriage or menstrual irregularities. prontogest works to replace the hormone progesterone, which prepares the uterine lining for pregnancy.