High-fat diet, obesity during pregnancy harms stem cells in developing fetus

Physician-scientists at OHSU Doernbecher Children's Hospital reveal a high-fat diet and obesity during pregnancy compromise the blood-forming, or hematopoietic, stem cell system in the fetal liver responsible for creating and sustaining lifelong blood and immune system function.

The life-long burden of a western-style diet on the heart and circulatory system have long been appreciated. However, prior to this study, no one had considered whether the developing blood stem cells might be similarly vulnerable to prenatal high-fat diet and/or maternal obesity. The findings are published in the journal Molecular Metabolism.

"Our results offer a model for testing whether the effects of a high-fat diet and obesity can be repaired through dietary intervention, a key question when extrapolating this data to human populations," said Daniel L. Marks, M.D., Ph.D., co-investigator and professor of pediatric endocrinology in the OHSU School of Medicine and Papé Family Pediatric Research Institute at OHSU Doernbecher Children's Hospital.

Several years ago, Marks and colleagues developed a mouse model that closely mimics the high-fat, high-simple-sugar diet currently consumed by many young women of childbearing age. Their subsequent research demonstrated that maternal overnutrition in mice significantly reduced the size of the fetal liver.

Armed with this information, Marks partnered with another stem cell expert, Peter Kurre, M.D., co-investigator on the current study and professor of pediatric oncology in the OHSU School of Medicine and the Papé Family Pediatric Research Institute at OHSU Doernbecher Children's Hospital.

Together, they discovered that the complex changes that occur as a result of maternal high-fat diet and obesity put significant constraints on the growth and expansion of blood stem cells in the fetal liver, which ultimately compromises the developing immune system.

Being very overweight, which is usually defined as having a body mass index (BMI) of more than 30, is increasingly common. Around 15-20% of pregnant women are now in this category. Your BMI is a measurement of how overweight you are and is calculated using your weight and height.

Before you get pregnant you can use the BMI healthy weight calculator to work out if you are overweight. But once you're pregnant this may not be accurate.

The best way to protect your health and your baby's wellbeing is to lose weight before you become pregnant. By reaching a healthy weight, you increase your chances of conceiving naturally and reduce your risk of the problems associated with being overweight in pregnancy.

Contact your GP for advice on how to lose weight. Your doctor may be able to refer you to a specialist weight-loss clinic. Find out more about losing weight before you become pregnant.

If you get pregnant before losing weight, try not to worry - good antenatal care can help minimise any risks to you and your baby.