Diagnosing vaginal bleeding with the presence of clots first depends on whether the bleeding is normal or abnormal. Normal vaginal bleeding relates to the periods (menstruation) and while any other bleeding may be considered abnormal, there may be a little blood after surgery to the vagina, cervix or uterus, or after an abortion, which is not unusual.

If blood clots are found with the period, this should not be a cause for concern as many girls and women experience this as part of their regular menstruation. Typically these clots tend to occur on the days of the heavy flow,  may vary in size and clots may appear darker than menstrual blood.

In instances of abnormal vaginal bleeding with the presence of clots, medical advice should be sought immediately. Emergency medical treatment is needed if severe cramping and abdominal pain is present, especially if you are pregnant or suspect pregnancy.

Why does menstrual clotting occur?

Clots with your periods are a result of the physiological changes that occur during the course of the menstrual cycle. The lining of the uterus thickens as a result of hormone action, primarily estrogen and progesterone, and subsequently sloughs off if pregnancy does not occur. This is then passed out as the menses (period).

Any bleeding leads to clotting but in menstruation, the body secretes anticoagulants to allow for this normal bleeding. to occur unhindered. In excessive vaginal bleeding, the anticoagulants may not be able to act as efficiently, resulting in clots being more often seen with heavy periods or any other cause of excessive vaginal bleeding.

What causes clots with vaginal bleeding?

Any causes of excessive vaginal bleeding, whether abnormal or not, may lead to clots. In addition, certain gynecological and systemic disorders may lead to vaginal blood clots, either as a result of heavy vaginal bleeding or occurring even with normal to light bleeding.

  • Menorrhagia – prolonged or heavy menses.
  • Intra-uterine devices (IUD’s), oral and injectable contraceptives or hormone replacement therapy (HRT).
  • Miscarriage – spontaneous or impending abortion.
  • Induced abortion.
  • Dysfunctional uterine bleeding – abnormal vaginal bleeding.
  • Peri-menopause.
  • Uterine fibroids.
  • Tumors affecting the uterus, cervix or vagina.
  • Polyps.
  • Adenomyosis.
  • Endometriosis.
  • Endometrial hyperplasia.
  • Anabolic steroids.
  • Clotting disorders leading to excessive clotting like thrombophilia or Von Willebrand’s disease.
  • Thyroid disorders.
  • Diabetes.
  • Cigarette smoking.
  • Any obstruction within the vagina or uterus may result in clotting and also cause dark or brown vaginal bleeding.

The cause of vaginal blood clots should be diagnosed by a doctor and blood tests and investigative techniques may first be necessary.


Article reviewed by Dr. Greg. Last updated on March 24, 2010