A study from the University of California at Riverside (UCR) examined immune cells from the umbilical cord blood samples of newborn babies born to lean, overweight, and obese mothers. The results showed for the first time that pre-pregnancy maternal weight influenced the immune system of the newborns, potentially putting the children at risk for conditions like asthma and heart disease. These changes are already detectable at birth.
According to the American Congress of Obstetrics and Gynecologists, more than 50% of pregnant women are overweight or obese. Fetuses of overweight or obese women are prone to develop congenital abnormalities, prematurity, childhood obesity, injury during birth, etc. Maternal obesity could also predispose her children to diseases in adulthood.
With this background, the current study, led by Dr. Ilhem Messaoudi, set out to find exactly when a baby’s immune system gets compromised if the mother is obese. Of the total of 39 study subjects, 11 were lean and 14 each was either overweight or obese. The criteria used for determining a woman’s weight status was the Body Mass Index or BMI. A woman was considered overweight if her BMI was 25-29.9 and obese if the BMI was 30 or above.
The results showed that babies born to mothers with high BMI when compared to those born to lean mothers, showed the following:
- A reduced responsiveness of specific types of immune cells called monocytes and dendritic cells, to bacterial antigens (monocytes and dendritic cells are critical regulators of inflammation and innate immune response).
- A reduction in CD4 T-cells (these cells are mediators of immune response).
- Reduced eosinophils (cells that respond to allergic asthma or asthma pathogenesis).
Regarding lower levels of eosinophils, the researchers speculate that these cells have probably already moved into the lungs, explaining why these children are more prone to asthma later in life.
“This could change how we respond to vaccination and how we respond to asthma-inducing environmental antigens,” Dr. Messaoudi said to UCR Today. “As we know, in the first two years of life, children typically receive plenty of vaccines. The questions that arise are: Are the responses to vaccines in infants born to obese moms also impaired in the first two years of life? Should we change how often we vaccinate children born to obese moms? Should we change practices of how much and how often we vaccinate?”
Dr. Messaodi has advice for would-be mothers (as reported in UCR Today):
“If you are thinking of becoming or are already pregnant, talk to your ob-gyn about weight management, weight gain, and the ideal targets for weight gain,” she said. “When moms come in for prenatal visits, doctors tell them about smoking, recreational drug use, and alcohol. But they should also be talking about weight and weight management. Obesity has serious repercussions for maternal health. It is associated with low fertility and success with pregnancy. Rates of gestational diabetes, preeclampsia, placental abruption,– all of these risks increase dramatically with weight gain and obesity. So it is important to talk to your doctor about ideal weight entering into pregnancy and throughout pregnancy.”
Written by Mangala Sarkar Ph.D.
Wilson, R., Marshall, N., Jeske, D., Purnell, J., Thornburg, K., & Messaoudi, I. (2015). Maternal Obesity alters immune cell frequencies and responses in umbilical cord blood samples. Pediatric Allergy and Immunology. doi: 10.1111/pai.12387
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