New Recommendations for Prenatal Testing
When I was a student doing a clinical rotation through the obstetrics unit, one of my memorable patients was Baby Boy M. Actually, it was his mother, Mrs. M., who I can never forget, with her long red hair and intelligent eyes behind studious, dark-framed glasses. It fell to experienced staff members to inform her before discharge that her darling baby boy had Down syndrome, a chromosomal birth defect resulting in mental retardation, heart defects and distinct physical characteristics. She certainly fit the profile – she was 36 years old, gravida 4, para 4 (four pregnancies, four live births). Mrs. M. accepted the information patiently and with no trace of disappointment, the way mothers have been accepting grave news about their children since the origin of our species. Baby Boy M. and his mother were sent home, armed with referrals and resources. As a young girl in Pennsylvania, one of my neighbors was an adult woman with Down syndrome, who lived quietly with her aging parents, doing little chores around the house and yard. We all meet charming people with Down Syndrome and other birth defects throughout our lives and as we mature we accept them as being like everyone else, just different in some predictable ways. Looking at this picture of a beautiful little girl, it is easy to see that a child is a child is a child.
Some people do not feel up to the challenge of raising a child with birth defects. Certainly, the challenge of raising any child is daunting enough for most of us! The March of Dimes asks us to remember January as National Birth Defects Prevention Month. Their website provides a list of recommended Prenatal Tests and the timing for scheduling these. On January 2, 2007, the American College of Obstetrics and Gynecologists (ACOG) announced new recommendations for screening all pregnant women for Down syndrome. Genetic counseling and testing for Down syndrome has been offered to all pregnant women over the age of 35, as the incidence of the defect, caused by an extra chromosome in the maternal egg, increases with the age of the mother. The decision to have the testing was fraught with difficulty as an amniocentesis increases the risk of spontaneous abortion, or miscarriage. If the test is positive, the parents are faced with making a decision about terminating the pregnancy. As a result of the screening offered to older pregnant women, the incidence of Down syndrome has decreased. The new guidelines propose that less invasive testing be done – ultrasound to measure the thickness of the neck of the fetus (nuchal translucency or NT) and a blood screening test analysis of two proteins in the mother's blood called beta-hCG (human chorionic gonadotropin) and pregnancy-associated plasma protein A (PAPPA). First-trimester screening between 10 and 14 weeks of pregnancy detects about 80% of fetuses with Down syndrome. If the tests done in the first trimester of pregnancy indicate increased risk of Down Syndrome, ACOG recommends the parents be offered genetic counseling, amniocentesis and chorionic villi sampling (CVS).
Image courtesy of chokole.