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A study in Sweden examined women who gained weight between pregnancies. And it finds those women put themselves and their infants at risk.
NPR's Patricia Neighmond reports on the research in the British journal Lancet.
PATRICIA NEIGHMOND: Doctor Sven Cnattingius specializes in reproductive endocrinology at Sweden's Karolinska Institute. He had an inkling that a woman who was overweight increased her risk of complications during pregnancy and delivery. This study shows he was right.
Doctor SVEN CNATTINGIUS (Karolinska Institute, Sweden): For example, if she gained seven to 10 pounds then she would increase her risk of diabetes by 30 percent.
NEIGHMOND: And gaining a total of 12 pounds doubled a woman's risk for diabetes. Cnattingius and colleagues examined medical records of 150,000 women. They checked their weight at the women's first prenatal visit. When the women became pregnant a second time, their weight was checked again - also during the first prenatal visit.
Researches suspected large weight gains would be problematic, but they were surprised that a weight gain of just seven pounds - remember that's a weight gain between pregnancies, not during pregnancy - that just seven pounds increased the woman's risk for a variety of complications, including...
Dr. CNATTINGIUS: Pregnancy-induced hypertensive diseases, diabetes, cesarean delivery, and high-birth weight babies.
NEIGHMOND: And there are several related factors that can lead to that increased risk of c-sections.
Dr. CNATTINGIUS: Primarily, I would say if she have a large baby, you are more likely to have a cesarean delivery. If you have pregnancy complications, such as high blood pressure or gestational diabetes, you are more likely to have a cesarean delivery.
NEIGHMOND: Women who gained weight were also at higher risk of delivering still-born babies. Researchers don't know why. As for diabetes, researchers say increases in weight increase blood sugars and that can increase diabetes risk.
Bottom line, researchers say? Women should work to keep their weight down, losing weight after pregnancy and keeping it off.
Doctor Aaron Caughey is a maternal-fetal specialist at University of California, San Francisco.
Doctor AARON CAUGHEY (Maternal-Fetal Specialist, University of California, San Francisco): Let's say she began her last pregnancy at 125 pounds. And ended up gaining, you know, 45 pounds and now is at 140. I would say getting back to that pre-pregnancy weight from the prior pregnancy would be a good idea before getting pregnant for the subsequent pregnancy, if she can do.
NEIGHMOND: But no fad diets, says Caughey, just good nutrition and daily exercise and if a woman can do it - breastfeeding.
Dr. CAUGHEY: Right now, breastfeeding is sold as - its benefits for the kids, right? I mean, we know that women who breastfeed their children are less likely to develop colds and get upper respiratory infections and ear infections. But I would suggest that breastfeeding also has an enormous benefit for the woman's health.
NEIGHMOND: Caughey says studies have shown when women breastfeed they lose more weight than women who don't breastfeed. And they even reduce their risk of diabetes.
Patricia Neighmond, NPR News.
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