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Researcher Warns about Gestational Weight Gain

By Eddy Ball
March 2008

Before her talk began, Siega-Riz, left, talked over logistics with the lecture host, NIEHS Fellow Rose Ramos, Ph.D.
Before her talk began, Siega-Riz, left, talked over logistics with the lecture host, NIEHS Fellow Rose Ramos, Ph.D. (Photo courtesy of Steve McCaw)
Investigator Olga Basso, Ph.D., who has major research interests in the field of reproductive epidemiology, had several questions about the speaker's findings on the incidence of diabetes in overweight mothers.
Investigator Olga Basso, Ph.D., who has major research interests in the field of reproductive epidemiology, had several questions about the speaker's findings on the incidence of diabetes in overweight mothers. (Photo courtesy of Steve McCaw)
Health Scientist Administrator Jerry Heindel, Ph.D., asked Siega-Riz about the problems of physician and patient compliance with efforts to encourage pregnant women to control weight gain.
Health Scientist Administrator Jerry Heindel, Ph.D., asked Siega-Riz about the problems of physician and patient compliance with efforts to encourage pregnant women to control weight gain. (Photo courtesy of Steve McCaw)
Siega-Riz enjoyed a little comic relief when a questioner confused a study she reported on with one she actually performed.
Siega-Riz enjoyed a little comic relief when a questioner confused a study she reported on with one she actually performed. (Photo courtesy of Steve McCaw)

Nutritional epidemiologist Anna Maria Siega-Riz, Ph.D., had good reason to sound alarmed when she talked about pregnancy and weight gain during her February 1 Frontiers of Environmental Sciences lecture in Rodbell Auditorium. According to the University of North Carolina at Chapel Hill professor, overweight and obese women, as well as women who gain too much weight during their pregnancies, may be endangering their own health - and the health of their children.

In her talk, "Maternal Obesity - The Number One Problem Facing Prenatal Care Providers in the New Millennium," Siega-Riz presented a preponderance of evidence that these women have a significantly greater risk of suffering from metabolic syndrome-related diseases, of bearing children with birth defects, such as spina bifida, and of giving birth to babies who will experience problems with their own health.

More women are overweight and obese worldwide, and more of them are gaining excessive weight during pregnancy. Compounding the problem, Siega-Riz added, is the complacency of many pregnant women and, even more disturbing, their health care providers.

"Maternal obesity is not unique to the United States," Siega-Riz said as she began her lecture. "It is occurring globally." Many developing countries are facing the same problems as the United States, with obesity rates between 20 and 30 percent. Not only are rates increasing, Siega-Riz noted, but obesity is also emerging as a health disparity issue due to its greater prevalence among minority women.

According to Siega-Riz, in the United States about a third of women are overweight and 10 to 15 percent are obese. The majority of pregnant women are gaining 21 to 40 pounds during pregnancy, and since the 1990s, there has been a 30 percent increase in the number of women who gain 40 or more pounds. "Only about a third of women are gaining weight within the targeted weight-gain recommendations," she said. In addition to the significant health problems that obesity contributes to on its own, such as diabetes and cardiovascular disease, Siega-Riz pointed to studies suggesting that about 25 percent of problems with fecundity and fertility are due to obesity.

Maternal overweight and obesity have been associated with a dramatic increase in risk for gestational diabetes, gestational hypertension, pre-eclampsia, caesarian delivery, fetal death and birth defects. The effects of overweight and obesity persist beyond childbirth and include post-partum weight retention, post-partum anemia related to the higher rate of caesarian sections, shorter duration of breast feeding and persistent glucose intolerance. Moreover, with excessive weight gain, a woman is also more likely to find herself in a higher weight classification at twelve months postpartum than she was at conception, putting her at even greater risk for complications in a subsequent pregnancy.

Because of these trends, physicians are seeing a growing number of pregnant women weighing as much as 300 pounds. "Quite frankly, they don't know how to manage them," Siega-Riz observed. One study found that 33 percent of subjects reported receiving no advice on gestational weight gain from their providers. The few intervention studies thus far have failed to show promising results and have found poor rates of compliance with interventions on the part of physicians and pregnant women.

As she and her colleagues strive to close the gaps in research on gestational weight gain, Siega-Riz continues to push for translation of this research through education and policy change. She currently serves a member of the Institute of Medicine's (IOM) Committee to Reexamine IOM Pregnancy Weight Guidelines. In 2004, she served on the IOM's Committee to Review the WIC Food Packages. As result of the recommendations from this committee, the USDA made the first major changes to the food packages since WIC's inception 30 years ago. In November 2007, the March of Dimes recognized her distinguished achievements in research, education and clinical services in the field of maternal-fetal nutrition with the Agnes Higgins Award.



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