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Threatened Abortion

(Threatened Miscarriage; Threatened Pregnancy Loss)

En Español (Spanish Version)

Definition | Causes | Risk Factors | Symptoms | Diagnosis | Treatment | Prevention


Threatened abortion is a diagnosis that is made during the first 20 weeks of pregnancy. While some women have vaginal bleeding in the first three months of pregnancy, bleeding and symptoms that could suggest an increased risk of miscarriage are called threatened abortion.

Fetus in First Trimester

Nucleus image
Copyright © Nucleus Medical Media, Inc.


Early-pregnancy bleeding can originate from the uterus, cervix, vagina, or the external genital area.

In many cases, the cause of the bleeding is due to a minor condition that requires no treatment. But if you have any vaginal bleeding during your pregnancy, especially if you also have abdominal pain, you should contact your doctor.

Possible causes of bleeding include:

  • Implantation of the embryo
  • Infection
  • Irritation (eg, after intercourse)
  • Miscarriage
  • Ectopic pregnancy (the baby develops outside of the uterus)
  • Molar pregnancy (rare growth inside the uterus)

Risk Factors

Factors that may increase the risk of threatened abortion include:

  • Infection
  • Trauma
  • Certain medicines
  • Advanced maternal age


The main symptom is bleeding during the first 20 weeks of pregnancy. Bleeding may be light or heavy. You may also have abdominal cramping.


Your doctor will ask about your symptoms and medical history. A physical exam will be done.

Tests that may be done include:


Talk with your doctor about the best treatment plan for you. Many cases of threatened abortion require no treatment at all. In other cases, treatment options include:

If you are bleeding heavily, your doctor may recommend bed rest. This has not shown to be beneficial, though. Your doctor may also want you to limit your activities.

Your doctor may prescribe progesterone . This is a female hormone that supports a pregnancy.

If your blood is Rh-negative and your partner's blood is Rh-positive, your doctor will give you an injection of Rho immune globulin. This will prevent your body from producing antibodies against your fetus' blood.

If you are diagnosed with a threatened abortion, follow your doctor's instructions .


While there is no clear way to prevent threatened abortion, you can take these steps to have a healthy pregnancy:

  • Get regular prenatal care.
  • Avoid alcohol, cigarettes, and drugs.
  • Limit caffeine intake.
  • Control any long-term conditions that you may have (eg, diabetes, thyroid disorder).
  • Talk to your doctor before taking any medicine. Some medicines can be harmful to your baby.
  • Avoid contact with toxins.

American Congress of Obstetricians and Gynecologists


American Pregnancy Association



Canadian Association of Pregnancy Support Services



Bleeding during pregnancy. The American College of Obstetricians and Gynecologists website. Available at: http://www.acog.org/~/media/For%20Patients/faq038.pdf?dmc=1&ts=20120814T1300076311. Accessed August 14, 2012.

Bleeding during pregnancy. American Pregnancy Association website. Available at: http://www.americanpregnancy.org/pregnancycomplications/bleedingduringpreg.html. Updated October 2008. Accessed August 14, 2012.

Last reviewed September 2013 by Andrea Chisholm, MD

Please be aware that this information is provided to supplement the care provided by your physician. It is neither intended nor implied to be a substitute for professional medical advice. CALL YOUR HEALTHCARE PROVIDER IMMEDIATELY IF YOU THINK YOU MAY HAVE A MEDICAL EMERGENCY. Always seek the advice of your physician or other qualified health provider prior to starting any new treatment or with any questions you may have regarding a medical condition.

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