ACOG Releases New Guidelines Recommending That All Pregnant Women Be Offered Screening for Down Syndrome in First Trimester

(Kaiser Daily Women's Health Policy)

The American College of Obstetricians and Gynecologists in the January issue of the journal Obstetrics & Gynecology released guidelines recommending screening for Down syndrome to all pregnant women in their first trimester, the Los Angeles Times reports (Maugh, Los Angeles Times, 12/31/06). Down syndrome is the most common major chromosomal abnormality in the U.S., occurring in about 5,000 infants born annually. Physicians often administer a blood test to pregnant women--especially women who are older or who have a family history of genetic abnormalities--in the second trimester around 16 weeks' gestation. If the blood test, known as the quadruple screen, is positive, the woman then undergoes an invasive tests called amniocentesis to confirm the diagnosis. A new method consists of performing an ultrasound test, called the nuchal translucency test, and a different blood test in the first trimester between 10 and 13 weeks' gestation. The nuchal translucency test measures the translucent space in the tissue in the back of a developing fetus' neck, which typically is larger in fetuses with Down syndrome because of excess fluid accumulation. The measurement then is put into a formula with the pregnant woman's age and the gestational age of the fetus to determine the likelihood that the fetus has Down syndrome (Kaiser Daily Women's Health Policy Report, 11/10/05).