You are what your mother ate: A mother’s obesity during pregnancy changes the way the fetal brain forms

By Christine Jasoni 21/05/2014

Is your mother to blame if you cannot resist chips? Or feel awkward at parties? Perhaps these questions make you imagine all the ways that you are similar to your mother, or the things that happened when you were growing up that helped shape the person that you are today. But now take one step back, to a time when you and your mother had an intimate relationship unlike any other – when you were in her womb – and ask those questions again.

Now, you’re probably thinking that this is starting to sound a bit weird, after all that was an awfully long time ago. But a mother’s health during pregnancy is important to the development of the unborn child and to its life well after birth. For example, insufficient folate during pregnancy can lead to spina bifida, a malformation of the neural tube, and ultimately the spinal cord, that can affect a person’s ability to function normally in daily life. And drinking alcohol can lead to fetal alcohol syndrome and children with learning disabilities. Fortunately, we have some control over these things – pregnant women are advised to take folate supplements and avoid alcohol. Mostly these recommendations are followed. But what about things that can happen during pregnancy that are unavoidable not so easily controlled? Can they also have an influence on offspring health?

Large public health studies that examined thousands of women have shown that a mother’s obesity during pregnancy can increase the risk that her offspring will suffer from obesity, diabetes, autism and learning disabilities[1,2]. A bit scary to think about. But what I hope you are asking is: why? Why does obesity during pregnancy cause life-long health problems in the child? Might an obese mother’s body somehow interact differently with the fetus and change the course of its life before birth?

New neuroscience research, from my group at the University of Otago (sorry for the indulgence here – I don’t usually write about my own work), suggests that this is exactly what happens. In this study, we used fetal mice as a model, so that the details of what’s happening in the womb could be discovered. We found that when a mother is obese during pregnancy her fetus develops fewer neural connections in areas of the brain that normally control eating behaviour; so the brain’s ability to control when and how much we eat doesn’t work quite right, and overeating results[3]. We also found that the obese mother’s body produced factors in the blood that were not present in mother’s of normal body weight, and that these made their way into the blood stream of the fetus[4].

The next step will be to try to reverse these changes and protect the offspring even when a mother is obese during pregnancy.  The brain has an amazing power to reshape itself after birth as we learn new things and new habits. So if we could teach the baby’s brain to form those connections properly or even form more of them, there is a good chance that body weight could be properly controlled after all.

This work was performed by PhD students, Tessa Sanders (Genetics) and Thomas Kim (Anatomy), and was funded by the University of Otago and Gravida: National Centre for Growth and Development.