Pregnancy weight gain liked to childhood obesity: Study

By Dr. Ananya Mandal, MDAug 4 2010

Women who gain excessive weight during pregnancy have a greater chance their babies will be born too big. Scientists are trying to find whether this relationship of gaining too much weight by mother and baby is genetic and can predispose the child to be obese later in life.

According to a new study published Wednesday in the journal Lancet, a woman's weight gain triggers her baby's size. This study, a first of its kind was conducted by researchers at Children's Hospital Boston who examined data from 513,501 women who had two or more live births. The number of babies in the study totaled more than 1.1 million. The researchers compared pregnancy weight gain and birth weights among siblings to control for genetic influences.

Compared with women who gained 18 to 22 pounds (a healthy weight gain for normal-weight women) pregnant women who gained 44 to 49 pounds were 1.7 times more likely to have a high-birth-weight baby. Here high birth-weight was defined as 8.8 pounds or more. Women who gained more than 53 pounds were 2.3 times as likely to have a high-birth-weight baby. Too much weight gain by mother also means diabetes and obesity for them later in life.

Many experts suggest that excessive nutrition in pregnancy creates an abnormal uterine environment that permanently changes the baby's brain, pancreas, fat tissue and other biological systems, said a co-author of the study, Dr. David Ludwig. He said, “Hormones and metabolic pathways, and even the structure of tissues and organs that play a role in body weight maintenance are affected.” Matthew Gillman of Harvard Medical School also working on this topic says follow-up studies are needed to establish the link between gestational weight gain and childhood obesity. Alan Fleischman, medical director for the March of Dimes also warned that, “Being severely underweight during pregnancy, as well as severely limiting food intake, can also be problematic to fetal growth and development.”