The Leading Causes of Birth Defects 

Amy Barczy

| 3 min read

Amy Barczy is a former brand journalist who authored content at Blue Cross Blue Shield of Michigan. Prior to her time at Blue Cross from 2019-2024, she was a statewide news reporter for MLive.com. She has a decade of storytelling experience in local news media markets including Lansing, Grand Rapids, Holland, Ann Arbor and Port Huron.

Pregnant woman on gynecological examination
Birth defects affect one in 33 babies born in the U.S. each year, according to the Centers for Disease Control and Prevention. Birth defects are wide-ranging: they can affect almost every part of the body. They’re structural changes present at birth that can be mild to severe. Some may impact how the body looks, or how the body works, or both. Because birth defects are so different, pinpointing the exact cause can be difficult. They can occur during any stage of pregnancy – but most occur during the first three months as the baby’s organs are forming. There’s a mix of factors that can put a baby more at risk of birth defects:
  • Genes: traits passed down from one generation to the next can affect risk of birth defects.
  • Behaviors: smoking, drinking, taking certain illicit drugs; taking certain prescription medications
  • Medical conditions: obesity and uncontrolled diabetes
  • Infections and illnesses: having a fever greater than 101 degrees Fahrenheit or having an infection including Zika virus or cytomegalovirus
  • Environmental exposures to toxic chemicals or pollutants
While most birth defects are found within the first year of a child’s life, they can be found before birth or at birth as well. Birth defects like cleft lips can be seen in an ultrasound, while others can be found during special tests during a pregnancy. However, these prenatal screenings don’t always find defects when they are present. Congenital heart defects are the most common birth defects in the U.S. and affect about 1% of all births each year. One in four babies with a congenital heart defect requires surgery within the first year of their lives. Medical care for babies with congenital heart defects continues to improve and survival rates for babies with critical defects have increased. Some congenital heart defects can be diagnosed during a special ultrasound called a fetal echocardiogram. The exact cause of heart defects in babies isn’t known. Down syndrome is the most common chromosomal birth defect. It’s caused by a chromosomal anomaly in which a person has an extra chromosome, which results in delays in physical and mental development. Down syndrome is relatively common and occurs in one in every 700 babies born in the U.S. each year. But some defects, like neural tube defects, can be preventable by following a healthy diet and getting enough folic acid. Additionally, fetal alcohol spectrum disorders – those caused by exposing a fetus to alcohol while in utero – are the leading preventable cause of birth defects in the U.S. For a healthy pregnancy, it’s important to take folic acid supplements and prenatal vitamins, to avoid alcohol, tobacco and illicit drugs, and to talk to your doctor about any prescription or over-the-counter medication you may use. Preventing infections and illnesses is also important and avoid overheating. Maintaining a healthy weight can also help, as well as managing any chronic health conditions like diabetes. The best way to understand your risk of possible birth defects is to talk with your health care provider and to regularly see them during your pregnancy. More from MIBluesPerspectives:
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