Weight gain by women during pregnancy could lead to heavier babies being born besides also exposing them to obesity related problems in future, says a new study.

Researchers in the United States studied the patterns of weight gain in more than half-a-million mothers who had had more than one child. They examined the cases one at a time so that the researchers could exclude genetics as the root cause of any maternal-offspring weight connection.

The investigators scanned through the data totalling more than 1,164,000 babies from U.S. state-based birth registries, including all known normal-term births in Michigan and New Jersey between 1989 and 2003.

Women who added more than 24 kilograms (53 pounds) during pregnancy were more than two times as likely to have a child that weighed at least 4 kg (8.8 pounds) at birth, as compared with women who packed on just 8 to 10 kg (18 to 22 pounds) while pregnant, the researchers found.

Overweight kids risk obesity related diseases as they reach adulthood, the study published in the August 4 issue of The Lancet, says.

"Because high birth weight predicts BMI (Body Mass Index) later in life, these findings suggest that excessive weight gain during pregnancy could raise the long-term risk of obesity-related disease in offspring," co-authors Dr. David S. Ludwig of Children's Hospital in Boston and Dr. Janet Currie of Columbia University in New York City have said.

"High birth weight might also increase risk of other diseases later in life, including asthma, atopy, and cancer," they say.

The authors noted that the link between mother's weight gain and baby's birth weight appeared to be consistent with every kilogram gained by the mother translating into an additional 7.35 grams (2 ounces) in baby weight.

Research is urgently needed on ways to help women of reproductive age attain and maintain a healthy weight before and during pregnancy, says Dr. Neal Halfon and Dr. Michael C. Lu from the Center for Healthier Children, Families and Communities at the University of California, Los Angeles, in a commentary accompanying the published study.

They believe that with a growing focus on pre-conceptional health, there is an opportunity to develop effective interventions to help women conceive at a healthier weight.