Medicine Reaction, Irregular Periods
Many prescription and nonprescription medicines can affect the menstrual cycle. A few examples are:
- Aspirin and other medicines (called blood thinners) that prevent blood clots.
- Nonsteroidal 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, Implanon or Nexplanon implants, and the levonorgestrel IUD (Mirena).
- Hormone therapy.
- Medicines used to treat cancer (chemotherapy).
- Thyroid medicines.
Current as of: May 1, 2026
Author: WebMD Ignite Staff
Clinical Review Board
All WebMD Ignite education is reviewed by a team that includes physicians, nurses, advanced practitioners, registered dieticians, and other healthcare professionals.