Gaining weight during pregnancy is inevitable.

But packing on pounds before pregnancy isn’t just avoidable.

It might also increase the risk of a birth defect called cleft palate, where bones forming the roof of the mouth don’t completely join together.

That’s according to a study published recently in the American Journal of Epidemiology.

It involved more than two-hundred-twenty-thousand Swedish women.

Researchers checked each woman’s weight at the beginning of her first and second pregnancy.

They noted how much weight was gained or lost, converting the changes to body mass index, a measurement that compares weight to height.

Then they looked at the incidence of cleft palate in babies from the second pregnancies.

Cleft palate was more than twice as common when the mother’s body mass index went up more than three points, compared with those whose B-M-I rose or fell one point or less.

The scientists also found cleft palate was almost three times as common when mothers took four years or more between pregnancies, compared with women who waited less than one year.

The researchers weren’t sure why weight gain was associated with cleft palate. But they speculated that undiagnosed type two diabetes might be a factor, because it’s associated with other birth defects. Dietary factors might play a role, too… excess fat intake or inadequate folate [“FOE-late”], for example.

In any case, the results provide one more reason for staying fit. Matter of fact, ensuring a healthy baby might be the best reason for doing anything.