Mom's Weight Can Be Big Risk for Baby

Plenty of moms-to-be kid about "eating for two" as they indulge their passion for ice cream or explain away those return trips to the buffet table. But jokes aside, if you're overweight before and during pregnancy, you're putting your baby at risk.

Being overweight or obese when you conceive increases the risk of your baby being born too soon. Premature birth rates have increased 29 percent since 1981, and being overweight is one reason why. Some other risk factors include a mother's age (being older than age 35 or younger than 19), carrying multiple fetuses, smoking, drinking, using drugs, eating poorly, poor prenatal care and not gaining enough weight.

Currently, more than 40 percent of nonpregnant American women, ages 15 to 49, are overweight or obese, which increases risks not only during pregnancy but also during a woman's entire life, according to Nutrition Today Matters Tomorrow, a report from the March of Dimes Task Force on Nutrition and Optimal Human Development.

"Weight before pregnancy matters much more than people realize, even health professionals," says Richard J. Decklebaum, M.D., professor of nutrition at Columbia University, NY, and chairman of the March of Dimes task force that developed the report on nutrition.

"Being overweight or obese before conception leads to big increases in risks for mother during pregnancy and big increases for risks for the baby," he says.

Mom's obesity double trouble for baby

Overweight mothers are not only more likely to have babies born severely premature, which is the single most important cause of infant death, they also are more likely to have children with birth defects. Furthermore, obese women are more likely to have higher rates of gestational diabetes, high blood pressure and toxemia and more likely to be hospitalized during pregnancy.

Studies have shown that obese women nearly double their risks of having a premature baby or a baby born with birth defects than women who are of a normal weight.

"These things get compounded more when you have other risk factors," Deckelbaum says. For example, if you are older than 35 when you become pregnant or if you are taking fertility drugs, you're raising the risks even higher.

There is a strong association between premature birth and birth defects. Defects in the neural tube, heart, intestine and large blood vessels are more common in children born to women who were obese before becoming pregnant.

However, it's not fully understood why obese women give birth prematurely, according to Deckelbaum. One factor may be that obese women may be more likely to have health problems during pregnancy, such as gestational diabetes and high blood pressure. Others have theorized that obese women aren't getting proper nutrition because of poor choice of food or some diet plan.

Lose weight before you get pregnant

If you are overweight and contemplating having a child, Deckelbaum says the best advice is to lose that excess weight before getting pregnant. If you are already pregnant and have a weight problem, then you will need to work on controlling your weight gain during pregnancy.

"Eating for two is not a license to go way overboard," Deckelbaum says.

Obstetricians follow specific pregnancy weight gain guidelines set by the Institute of Medicine. The guidelines, which are based on a woman's body mass index (BMI) - a calculation based on the relationship of weight to height - are as follows:

Women who gain more than the amount recommended during pregnancy were found in a Cornell University study to be four times more likely to be obese one year after giving birth, compared with women who gained within the recommended range. The study was sponsored by the National Institutes of Health.

Deckelbaum says the best "diet plan" is to eat a well-balanced diet in sensible portions. He cautions overweight pregnant women on going to extremes by crash dieting. The fact is, not enough is known about what effect zone diets, protein diets and other limited food-group diets have on the fetus, he says.

Keys to a healthy pregnancy

"The key is that women need to be aware that unhealthy lifestyles before pregnancy impact on what babies and families may look like later," Deckelbaum warns.

Deckelbaum and other experts recommend tips like these for a healthy pregnancy:

• Maintain a healthy weight.
• If you need to gain or lose weight, do so gradually (not more than 1 to 2 pounds a week).
• Engage in physical activity regularly 30 minutes a day, five days a week if your doctor approves.
• If you smoke, quit.
• If you are trying to become pregnant and you ordinarily drink alcoholic beverages, stop.
• To minimize your risk of having an infant with a neural tube defect (NTD), take a daily multivitamin containing 400 milligrams of the B vitamin folic acid every day, as part of a healthy diet; a healthy diet includes foods containing folic acid, such as leafy green vegetables, orange juice, peanuts, beans and fortified grains. It's important to talk to your doctor about whether you need additional folic acid supplementation especially if you are taking certain medications, or have a seizure disorder, for example. Also, if you are planning to become pregnant and have had a pregnancy affected by an NTD in the past, ask your doctor how much folic acid you should take.

External Sources March of Dimes Task Force on Nutrition and Optimal Human Development. Nutrition Today Matters Tomorrow, Feb. 25, 2002. Institute of Medicine. Nutrition During Pregnancy and Lactation: An Implementation Guide. Washington, DC: National Academy Press; update 1998.

This article was reviewed and updated June 2007.

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