We know the cause for some birth defects, but for most, we don’t. That’s because we think most birth defects are caused by a complex mix of factors. There are some factors that can increase the chance of having a baby with a birth defect. These are called risk factors and include:
• Smoking, drinking alcohol, or taking certain “street” drugs during pregnancy.
• Having certain medical conditions, such as obesity or uncontrolled diabetes.
• Taking certain medications, such as some acne drugs.
• Having someone in your family with a birth defect.
• Being an older mother, typically over 34.
• And exposure to some chemicals and viruses during pregnancy.
Having one or more of these factors doesn’t necessarily mean your baby will have a birth defect. It is important to talk to your doctor about what you can do to improve your chances to have a healthy baby.

This video can also be viewed at
https://www.atsdr.cdc.gov/toxtool/vi...