Does a newborn's vitamin D level relate to the mother's weight during pregnancy? Results from a study published in PLOS ONE (Public Library of Science) provides ample evidence that yes, higher body mass index (BMI) in mothers is associated with lower vitamin D levels in their babies. This is a concern, since low vitamin D at birth may be associated with reduced bone mineral density in the long term, as well as increased risk of allergic disease and obesity.

"Our study suggests that overweight or obesity in pregnancy is linked to lower vitamin D levels in both the mother and the newborn," sais Jami Josefson, MD, endocrinologist at Ann & Robert H. Lurie Children's Hospital of Chicago and assistant professor at Northwestern University Feinberg School of Medicine. "More research is needed, however, before we can make broad recommendations about the need for greater supplementation of vitamin D for overweight pregnant women."

Obesity in pregnancy has become increasingly common. In addition to lower vitamin D levels, it has been associated with heavier infants who then are at higher risk for childhood obesity and type 2 diabetes.

"I am very interested in studying the developmental origins of disease. If we can identify the most critical prenatal features, we can intervene during pregnancy to help prevent childhood obesity," says Dr. Josefson, first author of the publication.

Her previous research revealed that excessive weight gain in the first trimester of pregnancy is a risk factor for adverse pregnancy outcomes, including a large baby.

Currently, Dr. Josefson and Wendy Brickman, MD, also an endocrinologist at Lurie Children's, are involved in a follow-up to the large, international study that discovered the importance of increased maternal glucose level, even when it is not full blown diabetes. It was still associated with higher birth weight and body fat in the newborn. The follow-up study at Lurie Children's and nine other centers around the world sets out to see how those kids and mothers fare 8-12 years later.

"These observational studies will help us develop and test targeted interventions, so we can provide mothers and children the best opportunities for long-term health," says Dr. Josefson.