Amniocentesis is the most commonly prescribed invasive test performed during pregnancies in the United States. Most women fear them while doctors recommend them based on guidelines from the American College of Obstetricians and Gynecologists. These guidelines stem from past research studies and recommendations by the CDC that were based only on maternal age.
Studies that are decades old have suggested that amniocentesis increases the rate of miscarriage by 0.5% or 1 in 200 pregnancies. However, researchers at Mount School of Medicine in conjunction with other institutions involved in the First and Second Trimester Evaluation of Risk for Aneuploidy trial (FASTER trial) have just reported in the November issue of the journal Obstetrics & Gynecology, that pregnancy miscarriage rates after routine midtrimester amniocentesis are significantly lower than rates previously published years ago in the 1970s and 1980s.
This study reports that the amniocentesis procedure- related loss risk is approximately 1 in 1,600 pregnancies.
Amniocentesis, or an Amniotic Fluid Test (AFT), is a medical procedure used for prenatal diagnosis, in which a small amount of amniotic fluid is extracted from the amnion around a developing fetus. It is usually offered when there may be an increased risk for genetic conditions in the pregnancy.
Amniocentesis can be done as soon as there is enough amniotic fluid surrounding the fetus that a sample can be removed safely. Early amniocentesis can be performed as early as 13 weeks gestation. Standard amniocentesis is usually performed between 15 and 20 weeks gestation. Results take about two weeks. Often, genetic counseling is done before amniocentesis, or other types of genetic testing are offered.