In January, the American College of Obstetricians and Gynecologists (ACOG) released two new guidelines on: 1) screening for fetal chromosome abnormalities (aneuploidy) and 2) screening for hemoglobinopathies in pregnancy.

Traditionally, second trimester screening for Down syndrome, Trisomy 18, and neural tube defects has been available to pregnant women regardless of age, and invasive diagnostic testing (amniocentesis or chorionic villus sampling) offered to women over 35. ACOG looked at evidence from several large studies and is now recommending that first trimester screening for Down syndrome be offered to all pregnant women who present for prenatal care early in their pregnancy. This screening includes both an ultrasound measurement of nuchal fold translucency (thickness of the fetus's nape or back of the neck) and laboratory measurement of two biochemical markers (PAPP-A and free beta subunit hCG) at 8 to 11 weeks gestation. Women who choose first trimester screening for aneuploidy should be offered second trimester screening for neural tube defects.

ACOG also made additional recommendations on screening for hemoglobinopathies (hemoglobin variants and thalassemias). Individuals of African, Southeast Asian, and Mediterranean descent are at increased risk of being carriers of hemoglobinopathies and should be offered screening tests. If both parents are carriers, genetic counseling should be available. A complete blood count and hemoglobin electrophoresis or HPLC are appropriate screening tests.

Sources

S1
ACOG New Release (January 2, 2007). New Recommendations for Down Syndrome Call for Screening of All Pregnant Women. On the Internet: http://www.acog.org/from_home/publications/press_releases/nr01-02-07-1.cfm

S2
Obstetrics & Gynecology. 109: 217-227 (2007) -- Chromosomal Abnormalities.
Obstetrics & Gynecology. 109: 229-237 (2007) -- Hemoglobinopathies.