It has been known that overweight women have greater chances of having larger-than-normal babies but new research indicates that these odds stay higher even if a woman lost weight slightly before pregnancy.

The researchers study more than 146,000 women who'd each given birth twice. Those who maintained a normal body weight before each of their pregnancies had the lowest chances of giving birth to abnormally large newborns but those who were obese or overweight had higher risks of delivering large babies. That was not surprising.

The surprising was that women who had been overweight or obese but lost weight before their second pregnancy did not lower their increased odds of having an oversized newborns.

Researchers believe that extra weight, even after it's shed, may have long-term effects on subsequent pregnancies and they are suspecting through effects on mothers' metabolism.

Large newborns are at increased risk of birth trauma and often necessitate the use of cesarean delivery. Women who develop gestational diabetes have even bigger chances of having big babies.
Statistically, women who were overweight before both pregnancies were 70% more likely to have an overly large baby in their second pregnancy than normal weight women.

Those who managed to trim down to a normal weight before the second pregnancy also trimmed their risk of having a large baby. But the risk was not on par with that of women who'd been consistently slim.
Large babies can be prevented by preventing excess weight gain in the first place, researchers advise.