Newborns typically have a 1% chance of having a heart defect at birth. But for babies with Down syndrome, that risk is much higher.
“About half of all children with Down syndrome will be born with a congenital heart defect of some kind,” says Penn Laird II, M.D., a pediatric cardiologist at Pediatric Heart Specialists, The Heart Center at Children’s Health℠.
Why is Down syndrome associated with heart defects?
While the association between Down syndrome and congenital heart defects is well-known, the cause of heart defects isn’t clear. Genetics, particularly the extra 21st chromosome that all children with Down syndrome have, likely play a role in the development of heart defects.
“There is research into children with Down syndrome and heart defects showing they may be missing some genetic material. That material may be important to how the heart is supposed to form correctly,” says Dr. Laird. “But it’s not completely understood.”
When can a heart defect be detected in a baby with Down syndrome?
Down syndrome can be detected early on in pregnancy with a blood screening of the mother. In the past, parents worried that fetal heart rate or a white spot (echogenic intracardiac foci) on an ultrasound may be related to Down syndrome, but these factors are not necessarily associated with a Down syndrome diagnosis.
If a baby does have Down syndrome, a fetal echocardiogram and/or ultrasound between 18 and 21 weeks of pregnancy is necessary. These tests can reveal some heart defects before the baby is born.
The number of fetal diagnoses has increased dramatically in the last few years, thanks to new technology and testing, but not all children with Down syndrome are diagnosed before birth. If a child is born with Down syndrome and was previously undiagnosed during the prenatal period, then the baby will receive an echocardiogram before leaving the hospital after birth to check for heart defects.
What are the most common heart defects in babies with Down syndrome?
The most common heart defect in children with Down syndrome is an atrioventricular septal defect (AVSD), a large hole in the center of the heart. But other heart defects are possible and can occur, including:
Most major heart defects require one or more surgeries to correct, depending on their complexity and severity. Some minor heart defects may not require any surgery to correct, or even any treatment at all.
“Though there may be some differences in presentation and associated complications due to the presence of Down syndrome, that doesn’t change the way we treat children with a heart condition,” says Dr. Laird. “We use the same treatments for children with Down syndrome as we would for any child.”
While a heart defect or the prospect of heart surgery on a newborn can be frightening for any parent, Dr. Laird says new techniques are helping babies with congenital heart disease have healthy childhood years.
“Today, the outcome for a child with Down syndrome and a congenital heart defect is really excellent,” says Dr. Laird. “The vast majority of kids now can get their heart fixed in a very satisfactory way so they can live a totally healthy life.”