Testing the Waters
New and improved screening techniques can ease your concerns about your baby's health.
Will my baby be healthy? Of all the concerns that accompany pregnancy, this one usually tops the list. Despite the reassuring statistics that most babies are born normal, peace of mind is something that pregnant women crave even more than pickles and ice cream.
Tremendous advances in genetic testing have helped fulfill the need to know, but some of these tests pose a small amount of risk. Therefore, it’s important that all pregnant women be familiar with the value of the tests and who should take them.
Blood Tests and Ultrasound
Of all the genetic tests available, blood tests and ultrasound are the least invasive and most risk-free. Maternal-fetal medicine specialist John Williams III, M.D., of the Prenatal Diagnostic Center of Southern California in Beverly Hills, says that all women can benefit from alpha-fetoprotein (AFP), a blood test that screens for certain birth defects, and ultrasound, which provides a noninvasive sound-wave picture of your baby in utero.
Also called expanded AFP, this test of the mother’s blood is performed between weeks 15 and 20 to screen for conditions such as neural- tube defects, including spina bifida (a congenital defect in which the spinal cord fails to fuse completely, leaving nerves exposed) and Down’s syndrome (a condition that includes mild to severe mental retardation). Also referred to as a triple-marker blood test, AFP picks up about 90 percent of neural-tube defects and 60 percent of Down’s. If the test indicates a
higher-than-average chance of either condition, doctors usually recommend amniocentesis to get more definitive answers.
Using ultrasound, sonographers can check out a baby’s tiny structures, while expectant parents watch with awe. Depending on their experience and the machine’s resolution, sonographers can spot such conditions as spina bifida and congenital heart defects in fetuses. If your baby cooperates, the test also may be used to determine gender. One of the newest advances in fetal ultrasound is 3-D imaging, which can give an even clearer, more precise picture of the fetus.
Maternal genetic blood test
This test probably is three to five years away because it is still in the testing phase. However, it may prove able to yield genetic information early in pregnancy. Researchers at the University of California at San Francisco recently reported that they diagnosed two fetuses at risk for genetic disorders by analyzing the mothers’ blood in their seventh week of pregnancy.