Thursday, September 3, 2009

Dieticians call for action on overweight mothers-to-be

Medical Tribune July 2009 P16
David Brill

Overweight women should receive nutrition counseling before, during and after pregnancy, leading US dietitians have advised.

With the global obesity epidemic showing no signs of slowdown, the health of mothers and babies alike is at risk unless eating habits improve, cautions a recent joint statement from the American Dietetic Association (ADA) and the American Society of Nutrition (ASN).

Studies show that obese mothers are more likely to experience preeclampsia, gestational diabetes mellitus (GDM), gestational hypertension, postpartum anemia and cesarean delivery than women of normal weight. Their offspring, meanwhile, face an increased risk of birth defects, fetal macrosomia, childhood obesity and even perinatal death.

Ms. Ximena Jimenez, a consultant dietitian and national ADA spokesperson, said that healthcare professionals across the spectrum should work together to promote healthy eating and physical activity in women who are pregnant or planning to conceive. Physicians, for example, can play “a big role” in reinforcing the advice given by dietitians and other specialists, she said.

“A lot of the time it takes more than one type of counseling to get these women to change their lifestyle. I would encourage any healthcare professional to encourage these women to seek nutrition counseling,” she said.

“The principles are that you want them to increase whole grains and decrease refined carbohydrates like cakes, pastries and white breads. We also want them to replace saturated fat with healthy fats like omega-3 fats or fats from olive oil, canola oil or avocado, and also to increase their intake of fruits and vegetables. We also want them to be physically active,” she added.

Some 52 percent of women aged 20 to 39 in the US are overweight or obese (BMI 25 or above), according to data from the National Health and Nutrition Examination Survey of 2003-2004. Twenty-nine percent are obese (BMI 30 or above) and 8 percent are extremely obese (BMI 40 or above). Among adolescent girls aged 12 to 19, almost 32 percent are overweight or at risk of being overweight. [JAMA 2006 Apr 5;295(13):1549-55]

Despite the scale of the task, Jimenez remains optimistic that overweight women can be successfully counseled.

“I think it’s a very realistic target. There has to be promotion of healthy eating among women,” she said. “Imagine the benefits. As a society we are all going to benefit because we are going to have healthy women and healthy children.”

Jimenez highlighted studies showing the success of dietary interventions in overweight mothers, such as the Nurses’ Health Study, which found that risk of GDM was approximately halved by following a low-glycemic, high-cereal fiber diet. [Diabetes Care 2006 Oct;29(10):2223-30] The risk of preeclampsia can also be halved by taking calcium supplements, a meta-analysis of 12 studies shows. [Cochrane Database Syst Rev 2006 Jul 19;3:CD001059]

The new ADA / ASN position statement also reviews the literature on the prevalence of various pregnancy outcomes for overweight mothers and their babies. [J Am Diet Assoc 2009 May;109(5):918-27]

The risk of developing GDM, for example, is reported to double in overweight women, and increase over eightfold in the extremely obese. [Diabetes Care 2007 Aug;30(8):2070-6] Preeclampsia risk is around three times higher in pregnant women who are obese than those of normal weight. [Obstet Gynecol 2007 Feb;109:419-33]

The offspring of obese mothers are around twice as likely to have neural tube defects such as spina bifida, according to the US National Birth Defects Prevention Study. [Arch Pediatr Adolesc Med 2007 Aug;161(8):745-50] Oral clefts, hydrocephaly and cardiac abnormalities were also found to be more common in these infants than those born to normal-weight mothers.

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