Threatened Miscarriage

(Threatened Abortion; Threatened Pregnancy Loss)


Threatened abortion is vaginal bleeding and symptoms that suggest that a woman is at an increased risk of miscarriage. It happens during the first 3 months (or 20 weeks) of pregnancy. While some women will have bleeding in early pregnancy, a woman may or may not miscarry.

Fetus in First Trimester
Nucleus image

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Early-pregnancy bleeding can come from the uterus, cervix, vagina, or the external genital area. Bleeding is often due to a minor condition. Possible causes of bleeding include:

  • Embryo is implanting
  • Infection
  • Irritation, which may occur after sex
  • Miscarriage
  • The baby develops outside of the uterus—ectopic pregnancy
  • Molar pregnancy (rare growth inside the uterus)

Risk Factors

Things that may increase the risk of threatened abortion include:

  • Infection
  • Trauma
  • Certain medicine
  • Advanced maternal age


The main symptom is bleeding during the first 20 weeks of pregnancy. Bleeding may be light or heavy. Cramping may also be present.

Vaginal bleeding during pregnancy, especially with belly pain, should always be reported to a doctor.


The doctor will ask about your symptoms and past health. A physical exam will be done. Tests may be done to look for a cause. Tests, if needed, may include:


Many cases of threatened abortion require no treatment at all. Treatment, if needed, may include:

  • Bed rest or limited activity; may be needed for heavy bleeding
  • Medicine—to treat some causes; may include progesterone a female hormone that supports a pregnancy
  • Rho immune globulin—for mothers with Rh-negative blood; this will prevent the body from making antibodies against the fetus' blood


It is not always possible to prevent threatened abortion. Proper prenatal care may help to find and treat problems early.


American Congress of Obstetricians and Gynecologists

American Pregnancy Association


Canadian Association of Pregnancy Support Services

Health Canada


Bleeding during pregnancy. American Pregnancy Association website. Available at: Updated August 2015. Accessed March 19, 2020.

Bleeding during pregnancy. The American Congress of Obstetricians and Gynecologists website. Available at: Updated July 2016. Accessed March 19, 2020.

Deutchman M, Tubay AT, Turok D. First trimester bleeding. Am Fam Physician. 2009 Jun 1;79(11):985-94

Last reviewed September 2019 by EBSCO Medical Review Board Mary-Beth Seymour, RN  Last Updated: 7/17/2020