What Are Congenital Heart Defects?

Jimmy Kimmel shared an emotional story about his newborn son's battle with a congenital heart defect (CHD) last night on Jimmy Kimmel Live!. Kimmel said his son had something called "tetralogy of Fallot with pulmonary atresia," a heart defect that prevents the appropriate amount of blood from being pumped into the lungs. He recounted the whole experience, from the moment when a nurse realised his baby's skin looked a little blue, to what it was like to wait while a surgeon repaired his son's heart.

Kimmel used the opportunity to thank all the nurses who helped him, and then brought up an important point about healthcare: "Until a few years ago, millions and millions of us had no access to health insurance at all...if you were born with congenital heart disease like my son was, there's a good chance you'd never be able to get health insurance, because you had a pre-existing condition," he says. Today, Barack Obama tweeted in response to Kimmel's video, saying, "That's exactly why we fought so hard for the ACA, and why we need to protect it for kids like Billy."

If you've never heard of congenital heart defects before, or are curious if it's something you should be worried about, here's what you need to know.

Broadly speaking, congenital heart defects are any structural problems in the heart that develop before birth, according to the American Heart Association (AHA). Even though people use the terms "congenital heart defect" and "congenital heart disease" interchangeably, a CHD is not actually a disease — it just refers to an anatomical ailment or abnormality, according to the AHA. There are 20 main categories of CHDs, because there are so many different things that can go wrong, says Daphne Hsu, MD, a paediatric cardiologist at The Children's Hospital at Montefiore. The defects generally involve the interior walls of the heart, the valves inside the heart, and the arteries and veins that carry blood to the heart or the body, according to the National Heart, Lung, and Blood Institute (NHLBI).

It's not entirely clear what causes CHDs, but doctors know genetics have something to do with it. Parents who have a CHD are more likely to have a kid with the defect, too, but it's usually uncommon for more than one kid in a family to have one, according to NHLBI. A baby's heart starts to develop during the first six weeks of pregnancy, and it's around this time that a heart defect may also develop, according to the Mayo Clinic. "The heart is a complicated organ, and a lot of things regulate how the heart develops, so there are many things that could go wrong," Dr. Hsu says. Essentially what happens is that the "signals that tell the heart what to grow get mixed up," she says.

Certain environmental factors during pregnancy have also been linked to CHDs, such as smoking during pregnancy or taking medications, but Dr. Hsu says they try to make sure parents know that there's not much you can do to prevent CHDs. "In the end, we believe most of these things are related to genes, so it's not caused by things you do, or things you eat in the first trimester," she says.

Congenital heart defects are the most common type of birth defect, affecting eight out of every 1,000 newborns, which is 1% of births or about 35,000 babies per year in the United States, according to the NHLBI. CHDs are relatively easy to spot, because babies are closely monitored during the first 24 hours of their life, Dr. Hsu says. Some immediate signs that a newborn has a CHD include having blueish-grey skin, difficulty breathing, grunting, or flared nostrils, according to the Mayo Clinic. "People in the hospital are in-tune to looking for babies with this problem," she says. "There's quite a lot of wonderful oversight of babies to make sure they go home healthy."

Luckily, many CHDs are easy to treat, or require no treatment at all besides follow-up appointments with a cardiologist, Dr. Hsu says. Around 25% of babies with CHD have a critical CHD, and require surgery or other procedures in the first year of their life, according to the CDC. An estimated 1 million people in the United States are living with a CHD, and Dr. Hsu says that there's a "whole field of people who are surviving" from CHDs. If your child had a surgical "repair" on their heart as an infant, then later on when they grow up they may need to have the part replaced because their heart has grown, she says. "Most of the things we do surgery on makes the kids able to grow and have good lives," Dr. Hsu says. "They may need a valve replaced, but it's like repairing your car."