Women who have had children have a greater risk of becoming obese than women who have not, suggesting, researchers say, that efforts to reduce obesity should target women who have given birth, particularly minority mothers who seem to be especially at risk for obesity following childbirth.
In a study involving 2 923 women, researchers found that the relative risk of a woman becoming obese (over five years) was 3,5 times greater among women who had given birth than among those who did not have children.
None of the subjects were obese at the start of the study and all of the subjects were young, between 14 and 22 years old. Most (80 percent) were a normal weight. Sixty-five percent had not graduated from high school.
At the end of the five-year study, 52 percent had not given birth and 48 percent had at least one child. Of these women, 37 percent had more than one child.
The five-year incidence of obesity was 11,3 per 100 women who had given birth, compared with 4,5 per 100 women who had never given birth.
In addition, women who had at least one child and those who had two or more children had a three- to four-fold increased risk of becoming obese down the road, compared with women who had never given birth.
The five-year incidence of obesity was 8,6 per 100 women who delivered at least one child and 12,2 per 100 women who had two or more children.
The incidence of childbirth-related obesity was also higher among African American and Hispanic mothers than among White mothers.
Among the mothers who became obese in the two years following childbirth, only 11 percent returned to a normal weight in the remainder of the five years following childbirth, Dr. Esa M. Davis from Case Western Reserve University, Cleveland, Ohio and colleagues found.
In a report of the study, published in the online issue of the American Journal of Public Health, the investigators note that childbirth appeared to increase a woman's risk of becoming obese relatively soon after delivery.
"This finding is troubling," they say, because most women who become obese subsequent to childbirth remain overweight or obese" during the next five years.
"Our findings also showed that childbirth contributed to the racial disparities demonstrated in obesity levels," they also point out.