October 2, 2013
Weight Gain In Pregnancy Linked To Childhood Obesity
Brett Smith for redOrbit.com - Your Universe Online
According to a new Arkansas-based study, a woman’s weight gain during pregnancy has a direct impact on her child’s risk of obesity through age 12.
The study, which was published on Tuesday in the journal PLOS Medicine, included over 41,000 mothers and considered several confounding factors such as birth weight and genetics.
"From the public health perspective, excessive weight gain during pregnancy may have a potentially significant influence on propagation of the obesity epidemic," warned study author Dr. David S. Ludwig, an obesity prevention expert at the Harvard School of Public Health.
He suggested programs to restrict pregnancy weight gain may help prevent some cases of childhood obesity.
"Pregnancy presents an attractive target for obesity prevention programs, because women tend to be particularly motivated to change behavior during this time," Ludwig said.
The study researchers noted a familial tendency toward obesity. However, this tendency could be due to as shared genetics, environmental factors and socioeconomic conditions, and not necessarily to the impact of maternal weight gain.
To minimize the impact of genetics on their study, the researchers only considered mothers with two or more children – allowing them to compare children of the same family. Researchers considered the children’s body mass index (BMI) at almost 12 years, and then made comparisons between siblings. Data was taken from two databases of public records in Arkansas, where public school children must now have weight and height measured every other year.
The study team found mothers gained around 31 pounds on average during each pregnancy. For each kilogram (2.2 pounds) of pregnancy weight gain, the BMI of the child at age 12 increased by 0.02 (kg/m2). This significant increase remained even after the authors factored in differences in birth weight.
Researchers found pregnancy weight gain accounted for a 0.4 BMI difference in twelve-year-olds. As a point of reference, average body mass index of American children has increased by 2 (kg/m2) since the 1970s.
"Excessive pregnancy weight gain may make a significant contribution to the obesity epidemic," Ludwig noted. "Children born to women who gained excessive amounts of weight – 40 pounds or more – during pregnancy had an 8 percent increased risk of obesity” at age 12.
While that level of risk increase may seem relatively small on an individual basis, it could mean several hundred thousand cases of unnecessary childhood obesity around the world each year and untold levels of personal unhappiness, which could have a knock-on effect.
The authors admitted having the mothers' body mass index from before pregnancy would have given the study an even higher degree of accuracy, but said including this would have probably made the effect of pregnant weight gain even more pronounced, since women with a higher BMI tend to gain less weight when they become pregnant.
According to the study authors, their overall study findings are important because they imply “measures to limit pregnancy weight gain may help prevent obesity in the subsequent generation.”
The researchers also called for future studies to see how best to advise pregnant women on managing their weight gain during pregnancy.