Prometrium Progesterone 100 mg Capsules 100 Count (RX)Prometrium is a brand name for a medication called progesterone 100 mg capsules. Progesterone is a hormone that plays a key role in the menstrual cycle and pregnancy. Prometrium can be prescribed by a doctor to treat a variety of conditions, including irregular periods, menopause symptoms, and fertility problems. It is available as a capsule, typically taken once daily by mouth or inserted vaginally as directed by a healthcare provider. Prometrium