Likelihood of childhood obesity is linked to weight gained by mother during pregnancy

(Press-News.org) Women who gain excessive weight in pregnancy are more likely to have overweight and obese children, according to a new study published this week in PLOS Medicine. A study by David Ludwig from Boston Children's Hospital in the USA and colleagues has concluded that even after making allowances for differences in birthweight, the likelihood of a child becoming obese is linked to the amount of weight that the mother gained in pregnancy.

In order to find out whether childhood obesity was due just to the conditions during pregnancy (which influence birthweight) or whether other factors shared by mother and child (such as diet and genes) play a role, the study looked particularly at mothers with two or more children. The authors combined two large databases of public records in Arkansas, where it is now compulsory for all public school children to have weight and height measured every other year, allowing body mass index (weight/ height2) to be calculated.

The study showed that mothers gained around 14kg in each pregnancy. Using a within-family design, for each kilogram of weight gain during pregnancy, the body mass index of the child at age 12 increased by 0.02 kg/m2. This increase remained significantly increased even when the authors adjusted for differences in birthweight. Variations in pregnancy weight gain accounted for a 0.43 kg/m2 difference in childhood body mass index. For comparison, there has been an estimated 2 kg/m2 increase in average body mass index of children in the US since the 1970s.

The authors acknowledged that it would have been useful to have data on the mothers' body mass index from before pregnancy, but that including this would be likely to make the findings even more different (because women with a higher body mass index tend to gain less weight in pregnancy). The overall study finding is important as the authors conclude that 'measures to limit pregnancy weight gain may help prevent obesity in the subsequent generation.' Additional research is needed to learn how best to advise pregnant women on managing their weight in pregnancy.

### Funding: The collection of birth record and BMI data was supported by funds provided to Arkansas Center for Health Improvement (ACHI) from the state of Arkansas. Data analysis for this study was supported by subcontracts to ACHI from the National Institutes of Diabetes and Digestive and Kidney Diseases (K24DK082730) and from Princeton's Center for Health and Wellbeing. This work was also supported in part by a grant from the New Balance Foundation. The funders had no role in study design, data collection and analysis, decision to publish, or preparation of the manuscript. The content of this article is solely the responsibility of the authors and does not necessarily represent the official views of the National Institutes of Health or the National Institutes of Diabetes and Digestive and Kidney Diseases.

Competing Interests: DSL reported receiving grants from the National Institutes of Health and foundations for obesity-related research, mentoring, and patient care; travel grants from academic centers and professional associations for lectures; and royalties from a book about childhood obesity. DSL is a member of the Editorial Board of PLOS Medicine. HLR and JC reported no conflicts of interest.

Citation: Ludwig DS, Rouse HL, Currie J (2013) Pregnancy Weight Gain and Childhood Body Weight: A Within-Family Comparison. PLoS Med 10(10): e1001521.doi:10.1371/journal.pmed.1001521

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Contact:

Erin Tornatore
Boston Children's Hospital
UNITED STATES
617.919.3110
erin.tornatore@childrens.harvard.edu