Miscarriage - 
Causes, Incidence, & Risk Factors

A miscarriage is the spontaneous loss of a fetus before the 20th week of pregnancy. (Pregnancy losses after the 20th week are called preterm deliveries.) 

A miscarriage may also be called a "spontaneous abortion." This refers to naturally occurring events, not medical abortions or surgical abortions.

Causes

Most miscarriages are caused by chromosome problems that make it impossible for the baby to develop. Usually, these problems are unrelated to the mother or father's genes.

Other possible causes for miscarriage include:

• Drug and alcohol abuse
• Exposure to environmental toxins
• Hormone problems
• Infection
• Obesity
• Physical problems with the mother's reproductive organs
• Problem with the body's immune response
• Serious systemic diseases in the mother (such as uncontrolled diabetes)
• Smoking

It is estimated that up to half of all fertilized eggs die and are lost (aborted) spontaneously, usually before the woman knows she is pregnant. Among those women who know they are pregnant, the miscarriage rate is about 15-20 percent. Most miscarriages occur during the first seven weeks of pregnancy. The rate of miscarriage drops after the baby's heart beat is detected.

The risk for miscarriage is higher in women:

• Older age, with increases beginning by 30, becoming greater between 35 and 40, and highest after 40
• Who have had previous miscarriages

Symptoms

Symptoms Possible symptoms include:

• Low back pain or abdominal pain that is dull, sharp or cramping
• Tissue or clot-like material that passes from the vagina
• Vaginal bleeding, with or without abdominal cramps

Signs and tests
During a pelvic exam, your health care provider may see the cervix has opened (dilated) or thinned out (effacement).

Abdominal or vaginal ultrasound may be done in St. Vincent’s Antenatal Testing Unit to check the baby's development, heart beat, and amount of bleeding. Blood test can also be performed to help clarify the situation. 

Treatment

When a miscarriage occurs, the tissue passed from the vagina should be examined to determine if it was a normal placenta or a hydatidiform mole. It is also important to determine whether any pregnancy tissue remains in the uterus.

If the pregnancy tissue does not naturally exit the body, the woman may be closely watched for up to two weeks. Surgery or medication may be needed to remove the remaining contents from the womb. St. Vincent’s Family Birthing Center is equipped to handle these procedures.

After treatment, the woman usually resumes her normal menstrual cycle within four - six weeks. Any further vaginal bleeding should be carefully monitored. It is often possible to become pregnant immediately. However, it is recommended that women wait one normal menstrual cycle before trying to become pregnant again. 

For more information on miscarriages, please consult your physician. 

Contact us

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