Edwards Syndrome Testing - What You Need To Know

Edwards syndrome is a disorder characterized by abnormalities in the growth and development of babies, and may even result in miscarriage or stillbirth. Individuals diagnosed with this condition have three copies of the eighteenth chromosome, which is why Edwards syndrome is often referred to as trisomy 18.

Edwards syndrome is the result of a random error that occurs during the formation of either egg or sperm cells in the mother or the father. If an egg or a sperm cell that contains this error is fertilized, then the child will be affected.

The disorder affects 1 of 3,762 pregnancies in the United States. Although this risk seems small, health complications and physical abnormalities associated with Edwards syndrome are severe. These malformations and other health complications can be so life threatening that only 5-10% of diagnosed babies with Edwards syndrome will live past one year. For this reason, it’s important to understand how to monitor for this condition throughout pregnancy.

How is Edwards Syndrome Diagnosed?

Combined first-trimester screening includes an ultrasound that measures the nuchal translucency and a maternal blood test used to detect and measure certain substances indicative of this condition. Jointly, the results of these screening tests will indicate to your doctor if your child has a low or high risk of having a trisomy disorder.

Starting at week 10 of gestation, doctors may offer noninvasive prenatal genetic testing like the MaterniT® 21 PLUS to determine the risk that your baby has Edwards syndrome or other trisomy disorders. The test also screens for chromosomal abnormalities such as Down syndrome (trisomy 21) and Patau syndrome (trisomy 13), in addition to many other conditions that may affect the health of your child. This prenatal test uses a blood sample from the mother to screen for certain substances in order to analyze whether there is a low or high chance that the child has a trisomy disorder. Results of this test will allow your doctor to determine if further diagnostic testing should be proposed.

If screening tests indicate that there is a high risk that your child may be born with Edwards syndrome, your doctor will offer you the option of performing diagnostic tests. Since these tests are more invasive than screening tests, your doctor will often only present these options if screening results show a high risk of a chromosomal abnormality in your baby. Diagnostic testing for chromosomal abnormalities involves analyzing either a sample of the amniotic fluid or the placenta to look at the baby’s chromosomes. These tests will give your doctor an answer as to whether your child has Edward’s syndrome or not.

When your baby is born, if physical characteristics suggest Edwards syndrome, your doctor will take a blood sample from the baby to look at his or her chromosomes and confirm the diagnosis. 

Who Should Consider Testing for Edwards Syndrome?

The risk of having a child with Edwards syndrome increases with maternal age. For this reason, women of advanced maternal age 35 years and older may be offered testing by their doctors during a preconception or during the first prenatal appointment. Every pregnancy is different, and each couple has the right to accept or refuse testing during pregnancy. Knowing the likelihood your child may be born with a chromosomal abnormality will help you make the necessary changes and prepare for the arrival and care of your child.

Where Can I Learn More?

If you are planning a pregnancy or if you are currently pregnant and are interested in learning more about Edwards syndrome and testing options, talk to your doctor or with a genetic counselor. These healthcare professionals can help you find more information about conditions involving chromosomes in addition to how to monitor for these conditions during your pregnancy.