Jonathan Klein, MD, director of the Neonatal Intensive Care Unit of University of Iowa Children's Hospital within University of Iowa Hospitals and Clinics, offers these comments:

How many children in the U. S. are born with a birth defect?

Four million babies born every year in the United States, and out of that four million, about 3 percent, or 120,000, of these babies are born with a birth defect.  

What are some of the more common forms of birth defects?

The big four, most common birth defects include:

• Spina bifida, which is a defect in the formation of the spine
• Congenital heart defects
• Cleft lip and cleft palate
• Down Syndrome, or trisomy 21.

What are some of the typical causes of birth defects?

The causes of birth defects include environmental issues, genetic issues, infectious causes, and unknown; and 70 percent are still unknown.

If we look at some of the environmental causes, the most common would be folate deficiency, and this can lead to spina bifida, which again are defects in the spine. This can be prevented by having all women, prior to getting pregnant, be on multivitamins, including adequate amounts of folic acid.  

Other causes would be infectious, such as congenital viral infections like rubella or CMV or toxoplamosis. And certainly rubella can be prevented by making sure that women are vaccinated for rubella prior to getting pregnant.

There are other causes such as cigarette smoking and alcohol, so it's important to not do either of these things prior to and during pregnancy.

And certainly if the woman has any serious medical condition, it's best to have that optimized prior to getting pregnant, such as a woman with diabetes. If the diabetes is not controlled, that greatly increases the risk of a birth defect. So having good control of your diabetes prior to getting pregnant is critically important.  

Seventy percent of birth defects are unknown and there is promising research efforts underway to identify those causes. Every week, more and more genetic causes of birth defects are discovered. For example, scientists have discovered the genes responsible for cystic fibrosis; the genes responsible for many causes of muscular dystrophy; and they are finding more and more genes, and in many cases it's many different genes that are responsible for some of the more complex genetic problems. So with every year, this 70 percent number gets smaller as research progresses further.  

Which steps should people take to help reduce the risk for birth defects?

The most important thing is to actually live a very health lifestyle prior to even getting pregnant. Since most of the birth defects occur within the first three months of pregnancy when most people are unaware they're pregnant, it's critically important to be practicing these good habits prior to pregnancy, such as stop smoking, stop drinking, good healthy nutrition, taking the daily multivitamin with folic acid, and optimizing the health care of the woman if she has, for example, diabetes or hypertension prior to getting pregnant.

What is the most important advice for our listeners to keep in mind?

The most important advice is that most birth defects, unfortunately, are not preventable. Unfortunately, if there is a baby born with a birth defect, you don't want to develop a lot of guilt regarding this. There is a lot of ongoing research in terms of helping to learn how to prevent and detect birth defects and working on future ways of treating these. The idea is to always stay optimist and, again, always think about having a baby prior to getting pregnant is the best way to prevent the birth defect.  

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