TUESDAY, Nov. 13, 2018 (HealthDay News) -- Kids who were born large and whose mothers developed a form of diabetes during pregnancy have nearly triple the odds of becoming overweight or obese in childhood, new research shows.

"Just like smoking, alcohol consumption and other lifestyle choices, [women's] weight prior to getting pregnant, and weight gain and blood sugar control during pregnancy may have a significant impact on the future health of their children," said a Canadian team led by Dr. Padma Kaul of the University of Alberta, Edmonton.

One U.S. expert wasn't surprised by the findings.

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"A healthy pregnancy starts long before the patient is pregnant," said Dr. Jennifer Wu, an obstetrician/gynecologist at Lenox Hill Hospital in New York City. "During pregnancy, patients and doctors can work together to achieve ideal weight gain."

The new study involved more than 81,000 children born to mothers in the Canadian province of Alberta. Each child's weight was checked at their preschool immunization visits, between ages 4 and 6 years.

Rates of overweight/obesity were 43 percent among children who were larger than average at birth and whose mothers developed diabetes during pregnancy (a condition known as gestational diabetes). That's compared to just to 21 percent for kids who were average size at birth and whose mothers did not have gestational diabetes.

That means that the first group of children were about 2.8 times more likely to be overweight or obese than the second groups of kids, according to the study published Nov. 13 in the journal Diabetologia.

Rates of overweight/obesity were also higher among children who were born large and whose mothers had "regular" diabetes before their pregnancy (36 percent), the findings showed. Even with no maternal history of diabetes, however, 35 percent of children who were born large were still overweight or obese by the time they had their preschool vaccinations.

In fact, being a relatively large size at birth was calculated to contribute 39 percent to the risk of obesity in a child -- much higher than having a mother with gestational diabetes alone (16 percent) or pre-existing diabetes alone (15 percent), Kaul's group said.

Dr. Mitchell Kramer heads the department of obstetrics and gynecology at Northwell Health's Huntington Hospital in Huntington, N.Y. Looking over the new findings, he agreed that a baby's weight at birth is "a potentially modifiable factor."

Kramer said certain things -- the mom-to-be's weight, control of her blood sugar during pregnancy, and the weight she gains during the pregnancy -- may all come into play in reducing risks for her children.

"Also of note is that breastfeeding in the first five months of life was associated with a 25 percent lower likelihood of childhood overweight/obesity rates," compared with formula feeding, Kramer said.

More information

The American Academy of Family Physicians has more on childhood overweight and obesity.