How many people are affected by/at risk for congenital anomalies?

CDC estimates that congenital anomalies occur in about 1 in every 33 infants born in the United States each year.1

Congenital anomalies can occur during any pregnancy, but some factors increase the risk. The following situations place pregnant people at higher risk of having a child with a congenital anomaly:2

  • Lack of folic acid. People who are pregnant or who could become pregnant should take 400 micrograms of folic acid every day to prevent neural tube defects (NTDs). However, according to the Centers for Disease Control and Prevention (CDC), only 2 out of every 5 people of childbearing age take folic acid every day.3
  • Drinking alcohol. Drinking alcohol during pregnancy can lead to a variety of problems, including congenital anomalies. For example, using alcohol can lead to a fetal alcohol spectrum disorder, which is characterized by intellectual or developmental disabilities (IDD), physical challenges, and behavioral problems. There is no safe level of alcohol consumption during pregnancy.4
  • Smoking cigarettes. Smoking cigarettes during pregnancy can lead to a variety of problems, including lung problems such as asthma. Evidence also strongly suggests that certain congenital anomalies, such as cleft lip or cleft palate, are caused by smoking during pregnancy.5
  • Using drugs. Using drugs during pregnancy can increase the risk of various congenital anomalies, including IDDs and behavioral problems, as well as pregnancy loss and stillbirth.6
  • Medication use. Certain medications are known to cause congenital anomalies if taken during pregnancy. Thalidomide, which is currently used to treat certain cancers and other serious conditions, was once sold as a treatment for morning sickness until it was discovered that it caused severe congenital anomalies. Infants whose mothers took thalidomide had a range of structural and functional problems, including misshapen ears and shortened limbs. Although the thalidomide situation led to much stricter controls on drugs used during pregnancy, most medications currently used by pregnant people have not been tested for safety or efficacy in pregnant people. Addressing this issue is the primary focus of Maternal and Pediatric Precision in Therapeutics (MPRINT) Hub . People who are pregnant or who might become pregnant should discuss all medications, both prescription and over-the-counter, and supplements they take with their health care providers.7
  • Infections. People who get certain infections during pregnancy are at higher risk for having a child with congenital anomalies. Some of the more common infections linked to congenital anomalies are cytomegalovirus, a common virus that spreads through body fluids and usually causes no symptoms in healthy people, and toxoplasmosis, a parasitic infection that spreads through contact with cat feces, raw meat, and contaminated food and water. Zika virus infection is linked to microcephaly in newborn babies—a condition in which the brain and skull are atypically small. The Pregnancy topic has more information on infections that can cause congenital anomalies and other problems in newborns and on ways to prevent them during pregnancy, and CDC provides tips for preventing infections before and during pregnancy.
  • Obesity or uncontrolled diabetes. NICHD research found that the risk of newborn heart defects and NTDs increased with maternal obesity. Additional NICHD research suggest that children of parents with obesity may be at risk for developmental delays. Obesity is also associated with health problems and long-term health issues. Poorly controlled blood sugar places women at higher risk of having a baby who is too large, has breathing problems, or has other poor health outcomes. These outcomes are likely regardless of whether the woman had diabetes before she got pregnant (type 1 or 2 diabetes) or whether she developed diabetes during pregnancy (gestational diabetes).8
  • Exposure to things in the environment. Pregnant people who breathe in, eat, drink, or get things into their bodies in other ways may also be at increased risk of congenital anomalies. For example, pregnant people who are exposed to high levels of radiation, such as cancer treatments, are at higher risk for congenital anomalies in their infants.9 Handling or breathing in certain chemicals can also increase the risk of congenital anomalies.10

Citations

  1. Centers for Disease Control and Prevention. (2008). Update on overall prevalence of major birth defects—Atlanta, Georgia, 1978–2005. MMWR Weekly Report, 57(1), 1–5. Retrieved February 7, 2017, from http://www.cdc.gov/mmwr/preview/mmwrhtml/mm5701a2.htm
  2. Centers for Disease Control and Prevention. (2023). Preventing birth defects. Retrieved December 19, 2023, from http://www.cdc.gov/ncbddd/birthdefects/prevention.html
  3. Centers for Disease Control and Prevention. (2008). Use of supplements containing folic acid among women of childbearing age—United States, 2007. MMWR Weekly Report, 57(1), 5–8. Retrieved February 7, 2017, from http://www.cdc.gov/mmwr/preview/mmwrhtml/mm5701a3.htm 
  4. Tan, C. H., Denny, C. H., Cheal, N. E., Sniezek, J. E., Kanny, D. Alcohol use and binge drinking among women of childbearing age—United States, 2011–2013. (2015). MMWR Weekly Report, 64(37), 1042–1046. Retrieved February 7, 2017, from https://www.cdc.gov/mmwr/preview/mmwrhtml/mm6437a3.htm
  5. Centers for Disease Control and Prevention. (2022). Smoking, pregnancy, and babies. Retrieved December 19, 2023, from https://www.cdc.gov/tobacco/campaign/tips/diseases/pregnancy.html
  6. American College of Obstetricians and Gynecologists. (2021). FAQ: Tobacco, alcohol, drugs, and pregnancy. Retrieved December 19, 2023, from https://www.acog.org/womens-health/faqs/tobacco-alcohol-drugs-and-pregnancy external link
  7. Centers for Disease Control and Prevention. (2023). Medicine and pregnancy. Retrieved December 19, 2023, from https://www.cdc.gov/birth-defects/prevention/index.html
  8. Centers for Disease Control and Prevention (2022). What is diabetes? Retrieved February 22, 2023, from https://www.cdc.gov/diabetes/about
  9. Williams, P. M., & Fletcher, S. (2010). Health effects of prenatal radiation exposure. American Family Physician, 82(5), 488–493. Retrieved April 21, 2017, from https://www.aafp.org/pubs/afp/issues/2010/0901/p488.html external link
  10. American College of Obstetricians and Gynecologists. (2021). Committee Opinion 832: Reducing prenatal exposure to toxic environmental agents. Retrieved December 19, 2023, from https://www.acog.org/clinical/clinical-guidance/committee-opinion/articles/2021/07/reducing-prenatal-exposure-to-toxic-environmental-agents external link
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