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Do obesity & overweight affect pregnancy?

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How much a woman weighs when she gets pregnant and how much weight she gains during pregnancy can affect her health and that of her baby. Entering pregnancy with a normal body mass index (BMI) and gaining weight within the recommended levels during pregnancy are important ways to protect a mother's and a child's health.1

The Institute of Medicine recommends the following ranges of weight gain during pregnancy for American women:

  • Pregnant women who are underweight (BMI of less than 18.5) should gain 28 to 40 pounds.
  • Pregnant women at a normal weight (BMI of 18.5 to 24.9) should gain 25 to 35 pounds.
  • Overweight pregnant women (BMI of 25 to 29.9) should gain 15 to 25 pounds.
  • Obese pregnant women (BMI greater than 30) should limit weight gain to 11 to 20 pounds.1

Recent NICHD research shows that gaining more weight during pregnancy than recommended increases the risk for complications.

Obesity-related Health Risks for Mothers

Women who are overweight or obese during pregnancy face several possible health risks, including high blood pressure, gestational diabetes, and an increased chance of needing a Cesarean delivery.1,2

Gestational diabetes is diabetes that begins during pregnancy. Women who have had gestational diabetes are at a higher lifetime risk for obesity and type 2 diabetes.

Obesity-related Health Risks for Fetuses

The developing fetuses of obese women also are at increased risk for health problems. For example, researchers found a connection between maternal obesity and neural tube defects, in which the brain or spinal column does not form properly in early development. Also, research suggests that obesity increases a woman's chance of giving birth to a child with a heart defect by around 15%.2

Gestational diabetes also can cause problems for a newborn, including dangerously low blood sugar, large body size that may cause injuries at birth, and high bilirubin levels, which can cause other health problems.2

Children whose mothers had gestational diabetes also are at a higher lifetime risk for obesity and type 2 diabetes.2

Preventing Obesity and Overweight in Pregnancy

In light of the rise in rates of obesity in the United States, the American Congress of Obstetricians and Gynecologists encourages women to seek guidance about nutrition and weight reduction from a health care provider if they are overweight and considering getting pregnant.3

Good nutrition, staying active, and gaining the right amount of weight are important ways to promote a healthy pregnancy. The Weight-control Information Network provides tips on maintaining a healthy pregnancy.


  1. Institute of Medicine. (2011). Weight gain during pregnancy: Reexamining the guidelines. Retrieved August 8, 2012, from http://www.iom.edu/Reports/2009/Weight-Gain-During-Pregnancy-Reexamining-the-Guidelines.aspx External Web Site Policy [top]
  2. NICHD. (2012). NIH obesity research featured in HBO's The Weight of the Nation. Retrieved August 8, 2012, from http://www.nichd.nih.gov/news/resources/spotlight/pages/051112-HBO-obesity.aspx [top]
  3. Committee on Obstetric Practice. (2013). Obesity in pregnancy. Committee Opinion No. 549. American College of Obstetricians and Gynecologists. Obstetrics and Gynecology, 121, 213–217. Retrieved July 26, 2013, from http://www.acog.org/Resources_And_Publications/Committee_Opinions/Committee_on_Obstetric_Practice/Obesity_in_Pregnancy External Web Site Policy [top]

Last Updated Date: 09/27/2013
Last Reviewed Date: 12/30/2013
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