Risk of Miscarriage from Amnio Low

Study shows that amniocentesis, a test for genetic abnormalities in a fetus, is safer than we once thought.

For years, women have agonized over whether or not to have amniocentesis performed during pregnancy fearing a miscarriage risk of one in 200 pregnancies. New research proves there's far less to worry about than we thought - the current stats are closer to one in 1,600.

What Is Amniocentesis?
Amniocentesis involves inserting a needle into the abdomen to remove a small amount of the amniotic fluid surrounding the fetus. The fluid is then tested to diagnose or rule out various birth defects (including Down syndrome) and certain inherited diseases. The procedure is generally performed in the second trimester.

Women for whom amniocentesis is often recommended include those over 35, those who have a previous child with or a family history of birth defects or genetic disorders, and those whose blood tests have shown high levels of substances which may indicate abnormalities. What makes the test risky is that it's an invasive procedure, and any such procedure carries a degree of risk for the fetus.

Positive New Findings
A recent study, led by Keith Eddleman, MD, of New York's Mt. Sinai School of Medicine, and published in the November issue of Obstetrics & Gynecology, sought to determine if amniocentesis still has the 0.5% miscarriage rate (one in 200 pregnancies) that it did 30 years ago, when the last significant research was done. Dr. Eddleman offered amniocentesis to 35,000 pregnant women; 3,000 women opted to have it performed and the outcome was the same for both those who had the test and those who didn't -- about 1% of the women in both groups miscarried.

In this study the amniocentesis-related miscarriage rate was 0.06%, or one in 1,600 pregnancies -- significantly lower than the 0.5% rate that came out of studies performed in the 1970s. Since then, there have been many innovations in amniocentesis safety, the most significant being the use of ultrasound technology during the procedure - doctors are able to view the baby and therefore determine where to insert the needle.

According to Eddleman, the new findings "will have a significant effect on how women are counseled about amniocentesis by their doctors."