Recurrent Pregnancy Loss

With a thorough fertility evaluation, we are able to identify the cause of recurrent pregnancy loss (RPL) in 50 percent of couples. Potential causes are described below.

Chromosomal Cause

In approximately 4 percent of couples who experience RPL, one or both partners will have an abnormality of chromosome structure.

Anatomical Abnormalities

Abnormalities of the uterine cavity account for about 15 percent of RPL cases. Abnormalities may include a uterine septum (an abnormally-shaped cavity), scar tissue within the uterus, polyps or fibroids.

Immunological Causes

About 15 percent of couples with RPL have circulating antibodies that interfere with the proper function of the placenta, the tissue that supports the pregnancy. Blood tests can identify a set of these antibodies and, if found, the diagnosis of anti-phospholipid antibody syndrome (APS) can be made.

Blood Clotting Disorders (Thrombophilias)

Some women with RPL have inherited disorders that make them more prone to clots in their blood vessels. The link between thrombophilas and miscarriage is strongest for women experiencing losses in the late first trimester or second trimester.

Hormonal Abnormalities

Women with uncontrolled diabetes mellitus and uncorrected thyroid gland dysfunction have a greater risk of miscarriage.

Fetal Chromosomal Anomalies

As many as 70 percent of all miscarriages are due to abnormalities of the number of chromosomes in the fetus. Although this problem gets more common as women age, it occurs across all age groups. This type of miscarriage is often referred to as "random miscarriage."

Unexplained RPL

As many as 50 percent of RPL cases have no identified cause. Unexplained RPL can be very frustrating for couples. However, many studies have found that with continued attempts at conception and no additional interventions, the chances for a future live birth remain quite good for couples with unexplained recurrent pregnancy loss. Depending on age, these couples' chances for a live birth in future pregnancies range from 50 percent to 80 percent.

UCSF Health medical specialists have reviewed this information. It is for educational purposes only and is not intended to replace the advice of your doctor or other health care provider. We encourage you to discuss any questions or concerns you may have with your provider.