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Gestational weight gain does not influence offspring bone parameters in obesity
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In mothers with overweight or obesity, gestational weight gain was not associated with bone mineralization in offspring at age 7 years; however, researchers observed a modest association between gestational weight gain and offspring bone parameters in underweight and normal-weight women, according to study findings published in the Journal of Bone and Mineral Research.
“Our findings suggest that there is no advantage in gaining excess weight during pregnancy for the child's bone mass, particularly in women who enter pregnancy overweight,” Maria Teresa Monjardino, MPH, a doctoral researcher with noncommunicable diseases epidemiology unit at the Medical School of Porto University, Portugal, told Endocrine Today. “Our findings add skeletal health to the long list of maternal and child outcomes targeted by pregnancy weight-gain guidelines.”
Monjardino and colleagues analyzed prospective data from 2,167 mother-child pairs from the Generation XXI birth cohort, which included women from one of five public maternity units in Porto, Portugal, who gave birth from 2005 to 2006 (46.8% girls). At baseline, women completed questionnaires, and early pregnancy BMI and gestational weight gain were assessed. In a follow-up evaluation at 7 years, all children in the cohort underwent a whole-body DXA scan between December 2012 and August 2013. Mothers were stratified as either underweight/normal weight or as overweight/obese during early pregnancy, and researchers assessed gestational weight gain as a continuous measure using U.S. Institute of Medicine (IOM) guidelines. Researchers used local polynomial regression and smoothing spline models to assess the shapes of the associations between gestational weight gain and bone parameters in offspring, stratified by early pregnancy BMI group.
At the beginning of pregnancy, 35.8% of mothers had overweight or obesity. Mean gestational weight gain for mothers was 13.2 kg, and 36.6% of children were born to women who gained excessive weight during pregnancy by IOM standards, according to the researchers.
Women with a higher BMI in early pregnancy were more likely to have children with increased bone mineral content, areal bone mineral density and size-corrected bone mineral content at age 7 years, the researchers wrote.
Compared with women who had adequate gestational weight gain according to IOM guidelines, women in the underweight/normal-weight group with insufficient weight gain had children with an areal BMD on average 0.14 standard deviation (SD) lower (95% CI, 0.02-0.26) and a size-corrected bone mineral content on average 0.19 SD lower (95% CI, 0.07-0.3) at age 7 years, with results persisting after adjustment for confounders.
In women with overweight or obesity with inadequate weight gain, no such relationship was observed, according to the researchers.
“Interestingly, for both early pregnancy BMI groups, there were no differences in mean bone measures between children born to women with excessive [gestational weight gain] when compared to adequate [gestational weight gain],” the researchers wrote.
In sensitivity analyses restricted to participants whose information for early pregnancy weight was collected from the primary source, the associations between gestational weight gain and offspring bone properties persisted, according to the researchers.
“This study supports the inclusion of children’s skeletal health in the context of weight counseling during pregnancy,” Monjardino said. “Women should be informed that adherence to weight gain recommendations during pregnancy will also contribute to optimize their child’s skeletal health.”
Monjardino said she plans to assess whether the findings have long-lasting repercussions on children’s bone mass as they go through adolescence and enter adulthood.
“Hopefully, future generations of researchers will be able to find out whether maternal pregnancy weight gain will influence the most relevant long-term clinical outcome, ie, fragility fracture risk in older ages,” she said. – by Regina Schaffer
For more information:
Maria Teresa Monjardino, MPH, can be reached at the EPIUnit, Instituto de Saúde Pública, Universidade do Porto (ISPUP), Institute of Public Health of the University of Porto, Rua das Taipas 135, 4050-600, Porto, Portugal; email: teresa.monjardino@ispup.up.pt.
Disclosure: One of the study authors reports he has received personal fees from Alliance for Better Bone Health, Amgen, Eli Lilly, GlaxoSmithKline, Medtronic, Merck, Novartis, Pfizer, Roche, Servier, Takeda and UCB.
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