by Richard Lorenzo, D.O. board certified OB/GYN and Kerry Lorenzo, M.S. Licensed Genetic Counselor

Pregnancy is a very exciting time in a family's life.  It is also a time of great expectation and sometimes anxiety.  Early screening for genetic abnormalities is an option that every mother could consider.  The ways to investigate and try to ensure the health of a baby are vast and can be overwhelming.  Here we briefly summarize the options available.  The decision to pursue this type of testing is a very personal one that can only be made by each parent utilizing advice from your obstetrician/gynecologist, genetic counselor or other qualified healthcare provider.

The chance for most people to have a child with a health problem is 3-5%.  Additional factors that influence this risk include family history, parental age, ethnicity, and certain environmental exposures.  A family history of intellectual disability, autism, birth defects, chromosome or other genetic disorders should be discussed with your doctor.

There are several ways to screen a pregnancy for potential health problems.  The earliest test involves both a blood test and an ultrasound at approximately 11-13 weeks.  This is called the First Trimester Nuchal Translucency Screen because the ultrasound measures the fluid under the skin at the back of the baby's neck.  This test is one of the most sensitive tests to determine if the risk for a baby to have Trisomy 18 or Down syndrome is increased.

The Quadruple (Quad) Screen is a test in which the mother has her blood drawn to determine the chance for her baby to have Down syndrome, Trisomy 18 or an Open Neural Tube Defects (i.e. spina bifida).  It is performed between 15 and 21 weeks of pregnancy.

Newer testing involves isolating the baby's DNA from a blood sample from the mother.  This test is called Materni21 and it tests for the presence of chromosome problems including Trisomy's 13, 18, and 21.

All mothers have the option to test their pregnancy for a chromosome problem through chorionic villus sampling (CVS) or amniocentesis.  These tests are usually reserved for mothers who have abnormal screening tests or a family history of a genetic condition due to the risk associated with the procedures.  CVS is done between 10-13 weeks and amniocentesis is performed after 16+ weeks.  Both of these tests are very accurate (99.5%) but also incur a risk for a complication that could potentially lead to the loss of the pregnancy (0.5%).

All of these tests can offer valuable information to an expectant couple.  However, caution should be utilized when making the decision to pursue or decline these tests.  Parents should contemplate what they would potentially do with the information gleaned.