Lynestrenol is a progestin-only oral contraceptive. It is used to prevent pregnancy, as well as to treat menstrual disorders, such as irregular or absent periods. It works by preventing ovulation, thickening the cervical mucus to prevent sperm from entering the uterus, and by changing the lining of the uterus. Common side effects include nausea, breast tenderness, headaches, and spotting or breakthrough bleeding. Lynestrenol should not be used if you are pregnant or if you have certain medical conditions, such as a history of blood clots, breast or endometrial cancer, or liver disease.
Lynestrenol is a synthetic progestin, a man-made version of the female hormone progesterone. It is available in pill form and is used for two main purposes:
- Birth control: Lynestrenol is a progestin-only pill (POP), which means it contains only progestin and no estrogen. POPs work by thickening cervical mucus, making it difficult for sperm to reach the egg, and by thinning the lining of the uterus, making it less hospitable for a fertilized egg to implant. Lynestrenol is sold under brand names such as Exluton and Ministat.
- Treatment of menstrual disorders: Lynestrenol can be used to regulate irregular periods, treat endometriosis (a condition in which tissue similar to the uterine lining grows outside the uterus), and reduce heavy bleeding.
Lynestrenol is a relatively weak androgen, meaning it has some masculinizing effects. These effects are usually mild and may include acne, oily skin, or increased body hair. Lynestrenol does not have any significant estrogenic activity.
Lynestrenol is generally well-tolerated, but some common side effects include headache, nausea, breast tenderness, irregular bleeding, and mood swings. It is important to note that lynestrenol may not be as effective in preventing pregnancy as combination birth control pills (which contain both estrogen and progestin).