Prepregnancy Surgery for Severe Obesity Benefits Offspring


BOSTON — Severely obese women who underwent bariatric surgery and had major weight loss prior to pregnancy reduced the likelihood of macrosomia and subsequent obesity in their offspring, Dr. John G. Kral said at the annual meeting of NAASO, the Obesity Society.

What's more, the children of these mothers have been followed for 2–18 years and have no higher rate of obesity than does the larger age-matched background population in Quebec, where the study was done, he said.

The surgical procedure the women underwent was a pyloris-sparing biliopancreatic diversion (BPD), which is not only maldigestive but also malabsorptive. This of course raises concerns for pregnancy, with potential vitamin deficiencies, undernutrition, and low birth weight among the offspring, but the results have been reassuring, he said.

Dr. Kral and his coinvestigators from the department of surgery, Laval University, Quebec, followed a cohort of 45 children born before their mothers had surgery and 172 born after the surgery. The children are now aged 7 years or older, and in those born before surgery the prevalence of obesity is 60%, while among those born after the surgery the prevalence is 37%, said Dr. Kral of the State University of New York Health Science Center at Brooklyn.

According to the National Longitudinal Survey of Children and Youth in Canada, the overall prevalence of obesity among Canadian children in that age group is 38%.

Moreover, not only did the prevalence of obesity fall by 52% but also the prevalence of severe obesity fell by 45.1%, and there was no increase in low birth weight, he said.

Malabsorptive BPD surgery does not cause maternal stress or create “a famine situation in utero,” Dr. Kral said. Rather, it provides in utero benefits of energy homeostasis, euglycemia, and normalization of insulin and lipid levels, he said.

The odds ratio for obesity in children of very obese mothers is 60-fold, at least in part because of genetic factors, but by normalizing the fetal environment this surgery actually abrogates the genotype, he explained.

Dr. Kral and his coinvestigators had previously reported on a group of 783 women who underwent BPD and replied to a questionnaire that asked about pre- and postoperative pregnancies. Among the findings of that survey were that 82.6% of the women had a normal weight gain during postoperative pregnancy, the incidence of fetal macrosomia decreased from 34.8% to 7.7%, and the incidence of normal birth weight increased from 62.1% to 82.7%.

The investigators wrote, “We believe that the overall normalization of birth weights in these severely obese women is a consequence of the improved maternal physiological environment following BPD, including better glucose metabolism, lower blood pressure, and better hormonal function” (Obes. Surg. 2004;14:318–24).

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