First Trimester Screening
On January 2, 2007 the American College of Obstetrics and Gynecology (ACOG) came out with a recommendation that all pregnant women, regardless of their age, should be offered screening for Down syndrome between the 11th and 14th weeks of pregnancy.
Amniocentesis or chorionic villus sampling (CVS) used to be the only option to test for chromosomal abnormalities in women over 35 or women determined to be high risk pregnancies. First trimester screening offers risk assessment to women earlier in a pregnancy and with less risk to the baby.
The first trimester screening is a combination of a maternal blood test and a special ultrasound which identifies fetuses at increased risk for certain conditions like Down syndrome (Trisomy 21) and Trisomy 13 and 18 which causes multiple severe birth defects – the latter babies would likely die while still in the uterus or shortly after delivery. The blood test measures 2 proteins- free beta hCG and PAPP-A. The ultrasound measures fluid accumulation on the baby's neck, called nuchal translucency (NT). This test is safe for you and your baby as it does not present the same risks to the fetus as do an amniocentesis and CVS.
The Maternal-Fetal Medicine Division of Greenville Hospital System University Medical Group has staff certified in performing the first trimester screening ultrasound, and offers genetic counseling before and after the screening to explain the value and limitations of screening and the options available if the screening suggests the possibility of an abnormality. It is important to note the first trimester screening is just that – a screening. It determines whether or not you are at increased risk of carrying a baby with chromosomal abnormalities and whether further diagnostic tests are needed. The blood test and ultrasound can not be used to make an absolute diagnosis.
When selecting where to have first trimester screening done, it is important to note that the American College of Obstetricians and Gynecologists has advised that
- women found to be at increased risk of having a baby with Down syndrome with first-trimester screening should be offered genetic counseling and the option of CVS or mid-trimester amniocentesis.
- Specific training, standardization, use of appropriate ultrasound equipment, and ongoing quality assessment are important to achieve optimal NT measurement for Down syndrome risk assessment, and this procedure should be limited to centers and individuals meeting this criteria.
The Maternal-Fetal Medicine Division meets both of these criteria.
For more information about first trimester testing visit these Web sites and call Maternal-Fetal Medicine at (864) 455-1600.
American College of Obstetrics and Gynecology
Society for Maternal-Fetal Medicine
Universal Medication Form
