Levonorgestrel is a medicine used to manage emergency contraception. Modifying the way your body prepares for pregnancy, Levonorgestrel provides an option for unplanned moments.
Levonorgestrel belongs to a class of synthetic hormones called progestins, which act like the natural hormone progesterone. Levonorgestrel is the active compound in medicines such as Levlen and Plan B and helps prevent an unwanted pregnancy.
Levonorgestrel may be taken when a condom breaks, when a birth-control pill is missed, or after any other unexpected exposure to sperm. It is also used as a regular component of combined oral contraceptives to stop ovulation and keep you from becoming pregnant. Some people use it to help manage irregular periods or to space pregnancies. Levonorgestrel-containing products are aimed at reducing the chance of pregnancy after a single episode of unprotected sex or as part of everyday birth control.
When levonorgestrel enters your bloodstream, it mimics progesterone and signals the ovaries not to release an egg. It also thickens the mucus at the entrance to the uterus, making it harder for sperm to reach any egg that might be present, and changes the lining of the uterus so that a fertilized egg would have difficulty attaching.
Women who are pregnant, trying to become pregnant, or who are breastfeeding should use caution. People with liver disease, a history of blood-clotting disorders, hormone-sensitive cancers, or severe migraines may also need to discuss alternatives. Certain substances can lower levonorgestrel's activity, such as some anti-seizure medications, drugs that speed up hormone metabolism, and herbal products like St John's wort. Always read the specific medication's labeling for a full list of possible interactions.
People who smoke heavily, are over 35 years old, or have a history of clotting disorders may notice side effects more often. Those using other hormonal medicines or certain enzyme-inducing drugs can also experience stronger reactions.
Keep levonorgestrel products at room temperature, away from excess heat, light, and moisture, and store them out of reach of children. Different brands such as Levlen and Plan B may contain varying strengths, so the length of treatment can differ between short-term emergency use and ongoing daily use. For Levonorgestrel-specific instructions, refer to the medication information supplied with the product.
Progestin: A synthetic version of the natural hormone progesterone, used to prevent ovulation. Ovulation: The release of an egg from the ovary, which is required for natural pregnancy. Uterine lining: The inner tissue of the uterus that thickens each month to prepare for a possible pregnancy.
This article is an educational overview of levonorgestrel, not medical advice. Medicines containing this ingredient (Levlen, Plan B) may differ in formulation, strength, and directions. The information here does not replace professional clinical judgment. Readers should review their specific medication's labeling and seek guidance from a healthcare professional.
