‘Eating for two’ increases obesity risk for baby

EATING for two — or three — increases the chances of having a heavy baby at risk of becoming obese, research suggests.

Women who pile on the pounds when pregnant may be creating conditions in their womb that programme their future child for a lifetime’s struggle with weight, scientists believe.

And they will not be able to blame their genes, according to the research reported online in The Lancet medical journal.

Weight gain during pregnancy appears on its own to be responsible for high birthweight, the findings show.

Heavy infants are known to be predisposed to obesity in later life. They may also have an increased risk of asthma and cancer.

Previous studies have demonstrated that mothers- to-be who gain a lot of weight during pregnancy are more likely to give birth to an overweight baby.

But it was not known to what extent this association could be explained by genetics and other factors besides weight gain itself.

The research suggests that simply eating too much when pregnant, and gaining weight as a result, may be enough to put your baby at risk.

“These findings have important implications to general public health,” said Dr David Ludwig, one of the US authors.

“It’s appropriate for a baby to be born with some fat, but a baby born too fat indicates that the foetus developed in an abnormal environment during the most critical nine months of life.”

The scientists scoured US birth records to identify mothers in Michigan and New Jersey who had two or more births between 1989 and 2003. This allowed them to compare sibling infants and the same mother’s different pregnancies.

On average, women gained 30 pounds during their pregnancies with 12% gaining more than 44 pounds.

Heavy babies weighing 8.8 pounds or more accounted for 12% of all births.

Compared with those putting on just 18 to 22 pounds, expectant mothers gaining 44 to 49 pounds were 1.7 times more likely to have a high birthweight baby.

For those gaining more than 53 pounds, the chances more than doubled.

Comparisons between newborn infants and their brothers and sisters allowed genetic factors to be taken into account.

“When comparing between siblings to control for genetic influences, we found that increasing amounts of maternal weight gain led to the birth of progressively heavier infants,” said Dr Ludwig.

Studies suggest that excess weight, or weight gain, during pregnancy affect the womb environment and alter biological systems in the developing foetus that regulate body weight.

“Hormones and metabolic pathways, and even the structure of tissues and organs that play a role in body weight maintenance, are affected,” said Dr Ludwig.