Morbidly obese women who lose a large amount of weight after gastric bypass surgery before they become pregnant may help prevent their children from becoming obese, a new study shows. This is the first time this has been shown, investigators note in a report in the journal Pediatrics this month.
They compared the prevalence of obesity in 172 children, between 2 and 18 years of age, born to 113 mothers who were severely obese but lost weight after surgery with that of 45 siblings who were born before their mother’s gastric bypass.
Following mom’s surgery, the prevalence of obesity in the offspring fell by 52 percent and severe obesity by 45 percent. Among both boys and girls ages 6 to 18 years, the prevalence of overweight was reduced to levels seen in the general population.
Importantly, there was no increase in underweight children of mothers who had gastric bypass before becoming pregnant. "Operations such as these have the potential for causing harmful undernutrition, although women are cautioned to avoid pregnancy for at least 18 months after surgery," lead author Dr. John G. Kral from State University of New York Downstate Medical Center in Brooklyn noted in comments to Reuters Health.
The prevalence of obesity in the offspring of mothers who underwent obesity surgery prior to pregnancy is similar to population standards, suggesting the "abrogation of expression of obesity genes" in the offspring, the authors point out.
The researchers add that the beneficial effects of gastric bypass may be mediated by prevention of the harmful effects that excess pregnancy weight gain causes through "overnutrition" of the fetus.
"It is nothing short of remarkable that both genes and family environment are nullified by preventing overnutrition in the womb," Kral told Reuters Health.
Improved insulin sensitivity in the weight-reduced mother, fetus and placenta may also prevent "sugar-toxicity" in the fetus and infant. It may be that, after the surgery, the available calorie in the womb approximates normal rather than obese levels.
