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Reasons why heavy vaginal bleeding might be occurring

Spotting is very light bleeding that leaves only spots of blood on underwear and can’t fill a panty liner. Vaginal bleeding involves a significantly heavier flow.

What causes it?

Heavy vaginal bleeding is most commonly caused by pregnancy, uterine polyps, or fibroids. Less-common causes of include thyroid problems, polycystic ovary syndrome, ectopic pregnancy, and some infections, like pelvic inflammatory disease or chlamydia. Heavy vaginal bleeding can also be caused by medications and medical devices, like getting an intrauterine device (IUD) or changing birth control pills.


Heavy vaginal bleeding doesn’t always indicate a problem, but it’s still best to call your healthcare provider to report any bleeding or spotting that you notice.

  • Mayo Clinic Staff. “Vaginal bleeding: When to see a doctor.” MayoClinic. Mayo Foundation for Medical Education and Research, Apr 2016. Web.
  • American College of Obstetricians and Gynecologists (ACOG) Committee on Practice Bulletins — Gynecology. Practice Bulletin No. 128. “Diagnosis of abnormal uterine bleeding in reproductive-aged women.” Obstetrics and Gynecology. 120:197. Web. 2012.
  • “Menstruation and the menstrual cycle”. office on Women’s Health, US Department of Health and Human Services, Dec 2014. Web.

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