Having a baby is an exciting time and your mind is probably racing with hundreds of questions and concerns for you and your baby. One of the first concerns of all pregnancies is whether or not your baby is chromosomally normal.
It is important to remember that having a baby is chromosomally or genetically abnormal (such as Down Syndrome) is rare.
Until recently, only women who were considered “at-risk” for chromosomal abnormality received screening and diagnostic testing. A woman is considered at-risk if she is over the age of 35 or with a first degree relative (the expecting mother/father, maternal/paternal mother, father, sister or brother) with a chromosomal problem. If you are in the “at-risk” category, your obstetrician will recommend that you schedule an appointment with a genetic counselor. The genetic counselor will review your risk and offer additional screening and diagnostic testing. Just because you are in the “at-risk” category; it is still very unlikely that your baby will have a chromosomal abnormality.
In 2007 the American College of Obstetrics & Gynecology amended the recommendation for Down Syndrome and chromosomal abnormalities screening to include all women regardless of their age. Although the chance of having a baby with Down Syndrome is small in a woman who in not in the “at-risk” category; more than half of all children with Down Syndrome are born to women in this group.
New technological advances allow the EVMS Center for Advanced Fetal Therapy to provide safer, more accurate ways of detecting genetic problems, making it possible to perform screening and diagnostic testing in the first trimester from 10-13 weeks.
First Trimester Risk Assessment consists of an ultrasound to measure the skin thickness in the back of the baby’s neck, referred to as nuchal translucency (NT), and a blood test. These tests have no risk to the fetus. First Trimester Risk Assessment has an approximate 85% detection rate for Down Syndrome with a 5% false positive rate. It is important to remember that these screening tests evaluate the risk, or chance, that your baby could have a chromosome problem, but cannot identify a chromosomal abnormality in the fetus.
If your screening tests reveal an increased chance of a problem in your pregnancy, it does not automatically mean that your baby will be born with a problem. In fact, it is still very unlikely that your baby will have a problem. However, you will then be offered an opportunity to discuss your results further with a genetic counselor and you may elect to proceed with diagnostic testing.
The diagnostic tests performed in pregnancy are Amniocentesis or Chronic Villus Sampling (CVS). Although they are considered safe, diagnostic tests are invasive and carry a small risk of fetal loss (<1%). First trimester diagnostic testing via CVS allows for answers and decisions sooner.
If you would rather not pursue first trimester screening, second trimester screening for chromosome anomalies is available at our obstetrician’s office. If you are interested in second trimester screening, please discuss this with your doctor.
Do I need to have these tests? No. Screening and diagnostic tests are an option for you. No one has to have either a screening or diagnostic test.
Having a baby involves many complex decisions that are best made on an individual basis. There is no one correct answer for all women. Just as an abnormal screening test does not guarantee that your baby has a chromosomal abnormality, a normal screening test does not guarantee a healthy baby.
First trimester risk assessment offers sage, fast, and easy results that show the statistical likelihood of a child having Down Syndrome. If you are interested in first trimester screening for chromosomal problems, ask your obstetrician to schedule your appointment at the Eastern Virginia Medical School Center for Advanced Fetal Therapy.