Edwards syndrome, also known as trisomy 18, is a genetic condition that affects how a childs body develops. It is caused by an extra copy of chromosome 18, which is random and unpredictable. The likelihood of having a child with Edwards syndrome increases with maternal age at the time of pregnancy. However, anyone can have a baby with Edwards syndrome, and the condition does not usually run in families.

The effects of Edwards syndrome can be severe and can cause physical growth delays during fetal development. Babies with Edwards syndrome have slow growth before and after birth, and they may have heart defects, breathing problems, and other abnormalities in many parts of the body. Sadly, most babies with full Edwards syndrome will die before they are born. However, a small number of babies with mosaic Edwards syndrome (about 1 in 20) have an extra chromosome 18 in just some cells, which can lead to milder effects of the condition, depending on the number and type of cells that have the extra chromosome. Most babies with this type of Edwards syndrome who are born alive will live for at least a year, and they may live to adulthood.

There is no way to prevent Edwards syndrome, as it is the result of a genetic mutation. However, if you qualify for a combination of genetic testing and in vitro fertilization (preimplantation genetic testing), you can significantly reduce the chance of having a child with Edwards syndrome. If you plan on becoming pregnant and want to understand your risk of having a child with a genetic condition, talk with your healthcare provider about genetic testing.

Screening for Edwards syndrome is offered to pregnant women between 11 and 14 weeks of pregnancy. The screening test will show if the baby has a high or low chance of having Edwards syndrome. If screening shows that there’s a high chance the baby has Edwards syndrome, a further diagnostic test can be done to confirm the diagnosis.