Sometimes a Big Baby is Just a Big Baby

A Kaiser Permanente Center for Health Research study funded by the American Diabetic Association analyzed data from more than 40,000 women and found that those who gained more than 40 pounds during pregnancy were nearly twice as likely to have a baby weighing nine pounds or more.

According to this article in Medical News Today, this is the first study comparing women who gain more than 40 pounds, which is considered excessive (by whom is not mentioned) and women who are actively treating their gestational diabetes. Women who gain 40 pounds or more are more likely to have a “heavy baby” than their diabetes-treating counterparts.

Another finding is that 20 percent of women who gain 40 pounds or more have 9 pound babies, while 12 percent of women who gain less than 40 pounds have 9 pound babies.

“Too many women gain too much weight during pregnancy. This extra weight puts them at higher risk for having heavy babies, and these babies are programmed to become overweight or obese later in life,” said study lead author Teresa Hillier, MD, MS, an endocrinologist and senior investigator at the Kaiser Permanente Center for Health Research in Oregon and Hawaii. “A big baby also poses serious risks for both mom and baby at birth—for mothers, vaginal tearing, bleeding, and often C-sections, and for the babies, stuck shoulders and broken collar bones. ” [Emphasis mine]


This article follows in the wake of another urging pregnant women to “think twice about high-fat foods.” Inthis study from the University of Cincinnati and the Medical College of Georgia, researchers concluded that fat causes the placenta in rats to go into “overdrive” and overfeed the fetus.

Helen N. Jones, Ph.D., thefirst author of the study had this to say:

“We hope this research will ultimately help reduce the number of babies suffering from birth injuries, decrease C-section rates, and lower the risk of babies becoming overweight or obese later in life.”

Also quoted in the article was Gerald Weissmann, M.D., Editor-in-Chief of The FASEB Journal:

“It’s no secret that big women tend to have big babies, but now we know that there’s more at play than genetics. Cutting back on fatty foods during pregnancy might decrease the chance of having a baby that becomes overweight in the future.”


Of the many conclusions being drawn in these two studies, the most noteworthy are that macrosomic babies are programmed for obesity later in life by being larger than the average baby in utero, women can control the size of their babies by a) controlling their weight gain in pregnancy or b) eating less fat and that larger than average babies will cause birth injuries.


Almost one half of all cases of permanent brachial plexus injuries occur in infants weighing less than 4,500 g (9 lbs., 15 oz.).  That means one half does not.


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