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How many people are affected by/at risk for birth defects?

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The CDC estimates that about 1 in every 33 infants born in the United States has a birth defect.1

Birth defects can occur during any pregnancy, but some pregnancies are at higher risk than others. The following situations place pregnant women at higher risk of having a child with a birth defect2:

  • Lack of folic acid. Women who are pregnant or who could become pregnant should take 400 micrograms of folic acid every day to prevent neural tube defects (NTDs). According to the CDC, only 2 out of every 5 women of childbearing age, however, take folic acid every day.3
  • Drinking alcohol. Drinking alcohol during pregnancy can lead to a variety of problems, including birth defects. For example, using alcohol can lead to fetal alcohol syndrome, which is characterized by IDD, physical challenges, and behavioral problems. There is no safe level of alcohol consumption during pregnancy. According to the CDC, 1 of every 10 pregnant women, and more than one-half of the women who could become pregnant, have consumed alcohol during the past month.4
  • Smoking cigarettes. Smoking cigarettes during pregnancy can lead to a variety of problems, including lung issues such as asthma. Evidence strongly suggests that certain birth defects, such as problems with the heart and intestines, are caused by smoking during pregnancy.5 In addition, infants of mothers who smoke during pregnancy are at higher risk for sudden infant death syndrome (SIDS).
  • Using drugs. Using drugs during pregnancy can increase the risk of various birth defects, including IDDs and behavioral problems. For example, using cocaine during pregnancy increases the risk that the infant will be born with structural birth defects of the arms and legs, urinary system, and heart.
  • Medication use. Certain medications are known to cause birth defects 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 birth defects. 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, the majority of medications currently used by pregnant women have not been tested for safety or efficacy in pregnant women. Addressing this issue is the primary focus of the NICHD’s Obstetric-Fetal Pharmacology Research Units Network. Women who are pregnant or who might become pregnant should discuss all medications and supplements they take with their health care providers.6
  • Infections. Women who get certain infections during pregnancy are at higher risk for having a child with birth defects. Some of the more common infections that are linked to birth defects are cytomegalovirus (pronounced sahy-toh-meg-uh-loh-VAHY-ruhs), a common virus that spreads through body fluids and usually causes no symptoms in healthy people, and toxoplasmosis (pronounced tok-soh-plaz-MOH-sis), a parasitic infection that spreads through contact with cat feces, raw meat, and contaminated food and water. The CDC has more information on infections that can cause birth defects and other problems in newborns and on ways to prevent them during pregnancy.
  • Obesity or uncontrolled diabetes. Recent NICHD-supported research found that the risk of newborn heart defects increased with maternal obesity. Obesity is also associated with other health problems and long-term health issues. Poorly controlled blood sugar places women at higher risk of having a baby that is too large, that has breathing problems, and 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).7

  1. Centers for Disease Control and Prevention. (2008). Update on overall prevalence of major birth defects-Atlanta, Georgia, 1978-2005. MMWR Weekly Report, 57, 1-5. Retrieved July 18, 2012, from [top]
  2. Centers for Disease Control and Prevention. (2011). Guidance for preventing birth defects. Retrieved July 19, 2012, from [top]
  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, 5-8. Retrieved July 19, 2012, from [top]
  4. Centers for Disease Control and Prevention. (2004). Alcohol consumption among women who are pregnant or who might become pregnant-United States, 2002. MMWR Weekly Report, 53, 1178-1181. Retrieved July 19, 2012, from [top]
  5. Centers for Disease Control and Prevention. (n.d.). Risks from smoking during pregnancy. Retrieved July 19, 2012, from (PDF - 352 KB) [top]
  6. Centers for Disease Control and Prevention. (2011). Medication and pregnancy. Retrieved July 24, 2012, from [top]
  7. Centers for Disease Control and Prevention. (2011). 2011 National diabetes fact sheet. Retrieved July 25, 2012, from [top]

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