Medicines That Can Cause Changes in Menstrual Bleeding

Topic Overview

Many prescription and non-prescription medicines can affect the menstrual cycle. A few examples are:

• Aspirin and other medicines (called blood thinners) that prevent blood clots.
• Non-steroidal anti-inflammatory drugs (NSAIDs), such as ibuprofen (for example, Advil or Motrin) and naproxen (for example, Aleve).
• Hormonal forms of birth control, such as birth control pills, Depo-Provera injections, and the levonorgestrel IUD (Mirena).
• Hormone therapy.
• Medicines used to treat cancer (chemotherapy).
• Thyroid medicines.

If you are having changes in menstrual bleeding that you think may be related to medicine use:

• Call the doctor who prescribed the medicine to determine whether this is an expected side effect of this medicine. An appointment may not be needed.
• If you are taking a medicine not prescribed by a doctor, stop taking it. Call your doctor if you feel you need to keep taking the medicine or if you need help to control your symptoms after you stop the medicine.