Dec. 8, 2008 -- Breastfeeding may help new mothers shed the baby weight.

A new study examines the relationship between breastfeeding and postpartum weight retention. The study, which looked at data for more than 25,000 women participating in the Danish National Birth Cohort, measured how long women breastfed and also how intensely. Each woman received a breastfeeding score. Results showed that women with higher breastfeeding scores were more likely to lose their pregnancy weight six months after giving birth.

Researchers concluded that women who gain a reasonable amount during pregnancy and breastfeed exclusively are likely to lose all pregnancy weight six months after giving birth. They also estimate that women who breastfeed retain 2 kilograms (4.4 pounds) less than women who don't breastfeed at six months after giving birth.

Participants, all recruited by their doctors during their first prenatal visit, were interviewed four times -- twice during pregnancy, as well as six months after giving birth and 18 months after giving birth. They answered questions about their weight and how they were feeding their babies.

Postpartum weight retention is an important health topic, according to authors, because U.S. women of childbearing age "are alarmingly heavy." Fifty-two percent are overweight and 29% are obese, according to the study. These existing weight problems can be exacerbated by pregnancies.

Another key factor that contributes to postpartum weight retention is the amount of weight gained during pregnancy. Thirty-eight percent of American women gain more weight during pregnancy than recommended.

This study, published in the American Journal of Clinical Nutrition, provides one more reason to breastfeed. Current recommendations call for breastfeeding six months exclusively and to any extent until the baby's first birthday, according to the study.