GRAPEVINE, TEX. — Obese women who have bariatric surgery prior to pregnancy have less complicated gestations and their children are markedly less obese than are siblings born prior to mom's surgery, according to a Canadian study.
“Less obesity is not even the most important finding—it's the improvement in their metabolic condition. Children born after their mother's surgery had 30% less insulin resistance compared to their brothers and sisters born before the surgery. Regarding other elements of the metabolic syndrome, they also had a 20% decrease in triglyceride levels, their HDL was increased by 12%, and their waist circumference to height ratio was 11% better,” Dr. Picard Marceau reported at the annual meeting of the American Society for Metabolic and Bariatric Surgery.
The implication of these findings is that the propensity to develop obesity and metabolic syndrome is transmitted through the generations not only via genetic factors, but also epigenetically through the intrauterine environment, said Dr. Marceau of Laval University, Quebec City.
“Morbid obesity is a congenital and treatable disease,” he said. “The emphasis should be shifted from preventing undernutrition in pregnancy to preventing overnutrition in our affluent society. Surgery before pregnancy is a good option.”
He and his coworkers studied 37 very obese mothers who collectively gave birth to 56 children prior to undergoing a biliopancreatic diversion with duodenal switch (BPD) for weight loss and to another 54 children afterward. The investigators added another 10 morbidly obese women who had all 23 of their children prior to the BPD and 10 others who had all 19 of their children post surgery. Children born before the mother's bariatric surgery were prospectively followed on average to age 19 years, while those born post surgery were followed to age 10.
The mothers' preoperative body mass index averaged 48.5 kg/m
Pregnancies prior to bariatric surgery were marked by 12 cases of gestational diabetes, 9 of preeclampsia, and 15 of hypertension; pregnancies after surgery had none. Gestational weight gain averaged 13.8 kg/m
The birth weight of the children born after mom's surgery was 17% lower than that of their siblings born prior to surgery. The incidence of macrosomia was reduced by 86%.
Strikingly, the prevalence of severe obesity as defined by a BMI above the 90th percentile for age and gender was 75% less in the children born after the mother's surgery than in those born before.
The impact of the salutary postsurgical intrauterine environment differed somewhat in boys and girls. In boys, it was manifest mainly as less weight gain; boys born after the mother's surgery had an 86% lower prevalence of obesity than did their older brothers. In contrast, the main effects noted in girls born after the mother's surgery were a 40% reduction in insulin resistance and a 35% decrease in percent body fat, compared with their sisters born presurgically.
Interviews with the mothers indicated that the metabolic and weight differences between their older and younger children were not due to lifestyle changes; 80% of the moms said they did not change the quantity or quality of foods given to their children in the wake of their bariatric surgery. Plus, the differences between the two populations of children were noted from birth.
“The importance of this research cannot be overstated,” said discussant Bruce M. Wolfe. “The findings contribute tremendously to our understanding of the causes of obesity.”
Dr. Wolfe, professor of surgery at Oregon Health and Science University, Portland, expressed concern about nutrient deficiencies leading to fetal growth and developmental issues after bariatric surgery.
Dr. Marceau reported that there had been no problems with malnourishment in the children born after maternal surgery. Folic acid and vitamin B12 are unaffected by the operation. Pregnant patients who had the operation simply took a prenatal multivitamin.
The study was supported by the Canadian Institute of Health Research.
'The emphasis should be shifted from preventing undernutrition in pregnancy to preventing overnutrition.'
Source DR. MARCEAU