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Pregnancy & Healthy Weight

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New research shows that maintaining a healthy weight before and during pregnancy can reduce the likelihood of negative effects for mothers and babies

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We’ve heard the statistics: in 2007-2008, about one-third of adults in the United States were obese. We know the consequences: increased risks for coronary heart disease, high blood pressure, diabetes, cancer, and other conditions. Most of us would like to lose a few pounds to improve our health. Now women of childbearing age have another motivation for watching their weight: studies show that prepregnancy weight and pregnancy weight gain can impact not only pregnancy outcomes for mother and baby, but also their long-term health.

Findings from an NICHD study indicate that, compared to women at normal weight, women who are obese before pregnancy are much more likely to have babies with congenital heart defects, problems with the heart’s structure that are present at birth. Congenital heart defects change the normal flow of blood through the heart and can range from simple defects with no symptoms to complex defects with severe, life-threatening complications.

These findings and results from other research reveal that, for the best pregnancy and long-term outcomes, preconception care can really make a difference. Mounting evidence suggests that women need to think about a healthy pregnancy before they even start trying to get pregnant, and that taking actions to improve their health can greatly improve their babies’ health, both at birth and later in life.

For example, research from the NICHD and other organizations led the U.S. Public Health Service to recommend that women of childbearing age get at least 400 micrograms of folic acid, through food and/or supplements, for three months before pregnancy and for at least the first three months of pregnancy to prevent certain types of birth defects. Likewise, health care providers recommend that—before they even start trying to get pregnant—women receive immunizations or vaccines against diseases that could harm the developing fetus during pregnancy. The immunizations need to be administered several months before pregnancy to ensure healthy development of the fetus.

Women of childbearing age can take actions to help promote a healthy pregnancy even when they are not pregnant or planning to get pregnant. These can include:

  • Getting 400 micrograms of folic acid every day through foods or supplements
  • Keeping immunizations up to date
  • Adopting healthy behaviors, such as:
    • Avoid alcohol, illicit drugs, and smoking
    • Maintain a healthy weight and, if needed, lose weight
    • Eat a varied, healthy diet
    • Exercise regularly
    • Take a vitamin B12 supplement if you eat little or no animal products
    • Have a physical checkup
    • Have a dental checkup
  • Controlling any existing health conditions, such as diabetes, epilepsy, or depression
  • Avoiding exposures to toxic chemicals, hazardous substances, certain medications, and animal feces

The new findings suggest that, by losing weight before getting pregnant, obese women can reduce their babies’ risk for congenital heart defects. Previous studies have shown that obese women are also at higher risk for pregnancy-related problems, such as high blood pressure, preeclampsia, and gestational diabetes, for having longer labors, and for giving birth by cesarean section. Babies whose mothers were obese during pregnancy are at higher risk for having large bodies, which can lead to injuries during delivery, and certain birth defects. They are also at higher risk for developing Type 2 diabetes, and for developing it at a younger age than those whose mothers weren’t obese during pregnancy.

"Attaining a healthy weight before pregnancy is an important way for women to take charge of their—and their future babies’—health," said Caroline Signore, M.D., M.P.H., an obstetrician-gynecologist in the NICHD’s Pregnancy and Perinatology Branch.

Although it is important to get to a healthy weight before pregnancy, losing weight during pregnancy, even for obese women, can be dangerous to the developing fetus. Pregnant women need to get the right nutrition and gain the right amount of weight to promote healthy outcomes. Most women need only around 300 extra calories per day during pregnancy. In 2009, the Institute of Medicine released updated guidelines for weight gain during pregnancy External Web Site Policy, based on research from and consultation with the NICHD, other NIH Institutes, and the March of Dimes. Health care providers should discuss these guidelines with women who are pregnant or who are planning to get pregnant.

Women should always consult their health care provider before changing their diet or level of physical activity, especially if they are pregnant.

For more information on healthy weight and pregnancy, select one of the links below:


Originally Posted: April 7, 2010

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Last Updated Date: 03/21/2011
Last Reviewed Date: 03/21/2011
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