Definition
Miscarriage refers to the premature end of a pregnancy before the developing baby is able to survive outside the womb. Miscarriage can occur during the first or second trimester, before 20 weeks. Most occur in the first 12 weeks of pregnancy. They often are unexpected and isolated events. About 15%-20% of recognized pregnancies end this way.
Causes
Miscarriages often occur for the following reasons:
- Chromosomal abnormalities (common cause)
- Abnormalities in the uterine tract (eg, fibroids)
- Hormonal problems (eg, not having enough progesterone, a female hormone needed to support pregnancy)
- Factors related to the immune system (eg, may cause blood-clotting problems or rejection of the fetus)
- Trauma
In some cases, the cause is unknown.
Risk Factors
Factors that may increase the risk of miscarriage include:
- Having an infection
- Being older (maternal age of 35 years or older)
- Smoking, drinking alcohol, or using drugs
- Taking certain prescribed medicines
- Being exposed to certain environmental toxins
- Having a long-term condition that affects the immune system (eg, lupus, diabetes)
- Having high-dose radiation therapy on the ovary and uterus or the pituitary gland during treatment for childhood cancer
Having a miscarriage during your first pregnancy may place you at a higher risk for complications during your next pregnancy. These complications may include:
- Pre-eclampsia
- Threatened miscarriage
- Induced labor
- Preterm delivery
- Low birth weight
- Postpartum hemorrhage
Symptoms
Symptoms include some or all of the following:
- Vaginal bleeding
- Pink or brown discharge
- Cramping
- Passing the fetus, placenta, and surrounding membranes through the vagina
- Fever
Recurrent Miscarriage
While miscarriage usually is a one-time occurrence, up to 1 in 20 couples experience two miscarriages in a row, and 1 in 100 have three or more. In some cases, these couples have an underlying problem. Couples who have experienced two or more miscarriages should have a complete medical evaluation to learn the cause and how they can prevent another one from occurring.
Testing can reveal the cause of repeat miscarriages in at least 75% of couples.
- Chromosome problem in one member of the couple in 5%
- Uterine abnormalities in 10%-15%
- Hormone problems in 5%-40%
- Immune system problems in 5%-10%
- Unknown causes in 25%
Diagnosis
You will be asked about your symptoms, the length of your pregnancy, and when you first noticed a change in your condition. The doctor will perform physical and pelvic exams.
Prior to miscarriage, tests may include:
- Ultrasound testing—to assess the health of the fetus or detect an ectopic pregnancy (a pregnancy in which development occurs outside the uterus)
- Blood test—to check the exact amount of the hormone (called human chorionic gonadotropin or hCG) important to sustain an early pregnancy
After miscarriage, tests may include:
- Examination of the tissue that has passed through the vagina
- Blood tests—to check for a chromosomal error in the man or the woman or to check hormone and antibody levels
- Imaging tests—(eg, x-rays, ultrasound) to identify a problem with your uterus
- Endometrial biopsy—to check the uterine lining to see if it can support a pregnancy
- Hysteroscopy—to examine the inside of the uterus
Treatment
Immediate care usually involves observation only, especially in early or first trimester miscarriages. Medicine may be indicated in the event of heavy bleeding or cramping. A dilation and evacuation (D&E) may be needed if uterine contents are not spontaneously expelled (passed through the vagina). During a D&E, the doctor dilates the cervix, inserts a tool into the uterus, and suctions out remaining material.
Medications
Medicines to decrease the chance of miscarriage may include:
- Antibiotics for infection
- Hormone (progesterone) supplements
- Aspirin and other medicines to treat blood-clotting problems
Surgery
Some uterine problems can be corrected to prevent another miscarriage. Examples include:
- Uterine fibroids
- Septate uterus (tissue in the center of the uterus)
- Incompetent (weakened) cervix
Support Services
To help you deal with your loss, the doctor can refer you to a mental health therapist. You may also benefit from participating in a support group.
Prevention
Before you start to plan your next pregnancy consider the following regarding your health:
- Is your diet ready to support another pregnancy?
- Are there habits you should change prior to another pregnancy?
- What medicines are you taking and will they affect a pregnancy?
- How is your health?
- Are there issues you should resolve before trying another pregnancy?