The risk of amniocentesis resulting in miscarriage may be rarer than doctors have previously thought.
That news comes from a study of about 35,000 U.S. women who were 10 to nearly 14 weeks pregnant.
The study appears in Obstetrics & Gynecology. The researchers included Keith Eddleman, MD, of New York’s Mount Sinai School of Medicine.
The women were offered amniocentesis, in which doctors insert a thin needle through the belly to get a small sample of amniotic fluid, which surrounds the baby in the womb.
The test is used to check the baby’s risk for genetic conditions such as Down syndrome.
Most of the women -- nearly 32,000 -- declined amniocentesis. About 3,000 got amniocentesis.
About 1 percent of the women in both groups miscarried before 24 weeks of pregnancy.
The amniocentesis-related miscarriage rate by 24 weeks of pregnancy was 0.06 percent, or about one in 1,600 pregnancies studied.
That’s lower than the rate of 0.5 percent, or about one in 200 pregnancies, from studies done in the 1970s, before current amniocentesis techniques were in place, the researchers note.
Eddleman commented on the study in a Mount Sinai School of Medicine news release.
He says women’s decisions about amniocentesis “should be based on contemporary information about miscarriage rates with newer screening techniques, rather than just relying on general age-based risks.”
The findings “will have a significant effect on how women are counseled about amniocentesis by their doctors and the information they have when deciding about screening for their unborn child,” Eddleman predicts.
By Miranda Hitti, reviewed by Louise Chang, MD
SOURCES: Eddleman, K. Obstetrics & Gynecology, November 2006; vol 108: pp 1067-1072. News release, Mount Sinai School of Medicine.