Spontaneous abortion is a condition that occurs during the first 20 weeks of pregnancy in which vaginal bleeding suggests an increased risk of miscarriage .

Fetus in First Trimester

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Early-pregnancy bleeding can originate from the uterus, cervix, or vagina, or it can come from outside the genitals. In many cases, the cause of the bleeding is due to a minor condition that requires no treatment. However, if you experience any vaginal bleeding during your pregnancy, particularly if it is associated with abdominal pain, you should consult your doctor. Possible causes of bleeding include:

  • Implantation of the embryo
  • Infection
  • Irritation (eg, after intercourse)
  • Miscarriage
  • Ectopic pregnancy —the baby starts to develop outside the uterus, such as in a fallopian tube
  • Molar pregnancy—usually benign formations of placental cells (trophoblasts) in the uterus that can spread to nearby tissues and become malignant

Risk Factors

A risk factor is something that increases your chance of getting a disease or condition.

Miscarriage is common, with about 20-30% of pregnancies being complicated by bleeding in the first 20 weeks. About 10-15% of all established pregnancies ultimately abort (miscarry). Some factors thought to increase the risk of threatened abortion are:

  • Infection
  • Trauma
  • Certain medications
  • Advancing maternal age


The main symptom of miscarriage is bleeding during the first 20 weeks of pregnancy, with or without abdominal cramping. The bleeding may be light or heavy.


Your doctor will ask about your symptoms and medical history, and perform a physical exam. Other tests may include:

  • Ultrasound —a test that uses sound waves to examine the body
  • Fetal heart monitoring—a procedure that places electrodes on the abdomen to detect the fetal heart rate (detectable at 8-10 weeks of pregnancy), and determine the strength and duration of uterine contractions
  • Blood tests


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

Bed Rest

Your doctor may recommend bed rest if your bleeding is heavy. He or she may also give you instructions on limiting your activity.


Your doctor may prescribe progesterone , which is a female hormone that supports a pregnancy. It can also relax your uterus if you are experiencing a cramping uterus. Buphenine hydrochloride is another medication that can be used to relax your uterus.

Finally, if your blood is Rh-negative , and your partner is RH + your doctor may give you anti-D immunoglobulin. This will prevent your body from producing antibodies against your fetus' blood.

If you are diagnosed with a possible miscarriage, follow your doctor's instructions.


There is usually no way to prevent a threatened abortion. But things you can do to increase your chance of having a healthy pregnancy include:

  • Avoid alcohol, cigarettes, and illegal drugs
  • Limit caffeine intake
  • Control any medical conditions such as diabetes and hypothyroidism
  • Talk with your doctor before taking medications to ensure they are safe during pregnancy
  • Diagnose and treat infection (eg, bacterial vaginosis , gonorrhea ) as early as possible
  • Avoid contact with toxins (eg, arsenic, lead, polyurethane, heavy metals, organic solvents)
  • Get regular prenatal care