Overeating When Pregnant Can Harm Infant Health

It’s natural to eat more while you’re pregnant, but can overeating actually cause harm to your baby? New research says obesity is dangerous to your newborn, possibly even deadly.

In recent Breaking Muscle articles there has been discussion of the benefits of exercise during pregnancy. But what about eating right? Sometimes while pregnant, good nutrition can go right out the window. Because of the need for more energy and nutrients while pregnant, an increase in eating is to be expected and is a healthy part of the process, but there is a limit to what’s good for you and your baby when ramping up prenatal calories.

In a recent study at the University of Cambridge, researchers looked at several important health markers in infant newborn mice, after a pregnancy in which their mothers were fed excessive enough calories to cause obesity. While the newborn mice weren’t of abnormal physical size, they had a host of indicators of impaired health and future disease.

Firstly was increased cardiac hypertrophy. There are two kinds of muscle growth in the heart: the good kind that athletes experience, which makes their hearts pump more blood with greater efficiency, and then the bad kind that makes heart function suffer. The obesity diet caused the second kind of heart growth in the babies. The researchers examined six aspects of heart size, area, and weight and all were found to be increased. This kind of damage to the heart in humans is often the result of substantial physical stress. That could mean the excessive food intake of the mothers actually strained the unborn baby mice.

The heart wasn’t all the researchers saw. They also noted MAPK phosphorylation, which they indicated could lead to “pathological remodeling.” What that means is that unhealthy changes to the body could occur. For example, the various MAPK enzyme pathways are associated with bad stuff like inflammation and uncontrolled cell growth (as in cancer). The superoxide dismutase (SOD) activity was also reduced. SOD is a potent antioxidant existing in most living things. As mentioned earlier, there were indications of physical stress and the reduction of SOD was likely due to increased oxidative stress. When there is greater oxidative stress the kind of damage to the body that causes cancer may have already been significant. Finally, the mice had abnormal insulin activity, which impairs health metabolism and could lead to disease as well.

While working with mice allows for the researchers to more easily study the impacts of prenatal obesity, the question sometimes lingers: does this apply to people as well? The researchers believed that it does. Negative health impacts from obesity transcend species, and overeating while pregnant isn’t an exception.

Although it’s important to increase your intake of nutrients and calories while pregnant make sure that you focus on staying fit and healthy throughout the prenatal stage and while lactating. Not only will this keep you in good health, but will help ensure that your newborn is in good health as well.


1. Denise S. Fernandez-Twinn , et al., “The Programming of Cardiac Hypertrophy in the Offspring by Maternal Obesity Is Associated with Hyperinsulinemia, AKT, ERK, and mTOR Activation,” University of Cambridge, 2012

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