Maintaining a healthy weight in between pregnancies may have major implications for your baby's health.
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We all want to lose our baby bellies (and, ahem, hips, thighs, etc.), but now a new study published in The Lancet emphasizes the importance of moms achieving and maintaining a healthy weight post-pregnancy—for the health of their babies. That's because the pounds you pack on in between pregnancies has been linked to an increase in the risk of infant death from birth defects, lack of oxygen during birth, infections, SIDS, and stillbirth in a second pregnancy.

Even moderate increases in body mass index (BMI) in between pregnancies raises that risk, and even for mothers who were previously at healthy weights.

For the study, researchers looked at 450,000 Swedish women who gave birth to a first, then second child between 1992 and 2012. They found women of average height who gained about 24 pounds, or whose BMI rose more than four units between pregnancies, had a 50 percent greater risk of a second baby dying before four weeks of age, versus women who maintained their weight.

Women whose BMIs rose more than four points had a 60 percent higher risk. Meanwhile, moms who maintained healthy BMIs during a first pregnancy, but then gained between 13 and 24 pounds, or two to four BMI points, before a second pregnancy, had a 27 percent higher risk of infant death.

Conversely, overweight women who shed at least 13 pounds before a second pregnancy saw their risk of infant death fall 50 percent.

"Around a fifth of women in our study gained enough between pregnancies to increase their risk of stillbirth by 30 to 50 percent, and their likelihood of giving birth to babies who die in infancy increased by 27 to 60 percent, if they had a healthy weight during their first pregnancy," explains Sven Cnattingius, from the Karolinska Institute in Sweden.

It's worth noting the study only established a link between mothers' pounds increasing in between pregnancies and infant deaths, and not a direct cause-and-effect relationship.

"Our findings highlight the importance of educating women about maintaining a healthy weight during pregnancy and reducing excess weight before becoming pregnant as a way to improve infant survival," remarked the study's co-author Dr. Eduardo Villamor, from the University of Michigan School of Public Health. He stressed the importance of this research, given that half of U.S. women are overweight or obese when they get pregnant.

Melissa Willets is a writer/blogger and a mom. Follow her on Twitter (@Spitupnsuburbs), where she chronicles her love of exercising and drinking coffee, but never simultaneously.