Nuchal Translucency Screening.... Optional Testing During Pregnancy

Nuchal Translucency Screening …
Optional Testing During Pregnancy

By Valerie Jacques, RN, CPM, NHCM

This is the seventh in a series of articles exploring testing procedures available for you and your baby during pregnancy

This test, also called the Nuchal Fold Scan, is a prenatal screening test designed to help your healthcare professional access your baby’s risk for chromosomal abnormalities such as Down Syndrome. The test can also be used to detect major congenital heart problems. Testing must be performed when you are between 11 and 14 weeks pregnant (if you want the test performed, the last day that you can have it done is the day you turn 13 weeks and 6 days).

Nuchal Translucency Screening is painless, and poses no risk to you or your baby. However, it does not provide definitive diagnostic data, but is much less invasive than other tests such as CVS (testing a sample of Mom’s chorionic villi cells from her placenta), or amniocentesis (testing a sample of Mom’s amniotic fluid), and it can help you to decide if you want to have additional testing performed.

Ultrasound is used to measure the translucent space in the tissue at the back of your baby’s neck… that measurement is the key to determining risk. Babies with more fluid in the translucent space described above (during the first trimester), cause this space to be larger, indicating potential problems. Babies accumulating more fluid at the back of their neck during the first trimester are more likely to have abnormalities, although this test is not conclusive.

To begin the test, the sonographer confirms your baby’s gestational age. This is done by measuring the length of your baby from head to rump and comparing the measurement to standard data to determine if he/she is about the right size for his/her age. Next, a sensor (transducer) is positioned over Mom’s abdomen so that baby’s nuchal fold area shows up on the monitor. Finally, the sonographer uses a caliper (measuring device) to measure the thickness of the space in the fold.

Your baby’s nuchal fold measurement (which normally gets thicker every day) will be used in a formula (which includes your baby’s gestational age and your age) to determine your baby’s chances of having a chromosomal abnormality. Previous data gathered from this test (from thousands of babies) have allowed researchers to build a statistical database, which makes this possible. In general, the thicker the nuchal fold measurement at a given gestational age, the higher chance for chromosomal problems.

Knowledge is power! The more informed you are, the better prepared you will be to make decisions regarding your health and the health of your baby. For more information on these and other tests during pregnancy, speak with your health provider. Also, look for more information contained in the Informed Consent Agreement provided by your health professional.

Valerie Jacques is a NH Certified Midwife, a Certified Professional Midwife, an RN, and the owner/operator of Coastal Family Birth Retreat in Stratham, NH. She can be reached at 603-502-9452, or at http://www.coastalfamilybirthretreat.com/.