Mother's obesity may weaken baby's immunity

Babies born to obese mothers are likely to have weaker immunity than those born to lean mothers, says a new study. Pre-pregnancy maternal weight has a significant impact on the immune system of the newborns, putting such children at risk for potential diseases such as heart disease and asthma, the findings showed.

"A number of studies have linked maternal obesity - starting pregnancy with excess weight and gaining a lot of weight during pregnancy - to a higher incidence of cardiovascular disease and asthma in children," said lead researcher Ilhem Messaoud, associate professor at University of California, Riverside, in the US.

"Our study offers potential links between changes in the offspring's immune system and the increased susceptibility and incidence of these diseases later in life," Messaoud said. The pilot study involving 39 mothers in the US investigated key innate and adaptive immune cells in umbilical cord blood samples collected from babies born to lean, overweight and obese mothers.

"We found that very specific immune cells in circulation isolated from babies born to moms with high body mass index (BMI) were unable to respond to bacterial antigens compared to babies born to lean moms," Messaoudi said. "Such babies also showed a reduction in 'CD4 T-cells.' Both of these changes could result in compromised responses to infection and vaccination," Messaoudi said.

CD4 T-cells are essential for the human immune system. Further, the researchers found that cells that play a role in allergic response and asthma pathogenesis were significantly reduced in the umbilical cord blood of babies born to obese mothers.

One potential explanation for these observations is that these cells have already moved into the lungs, which could explain the increased incidence of asthma observed later in life in children born to obese mothers. The findings are forthcoming in the journal Pediatric Allergy and Immunology.