Mom’s Poor Health Increases Baby’s Risk for Autism and Other Disorders
A major study has found that when pregnant women are obese or have correlating conditions such as diabetes and high blood pressure, their children are more likely to be born with autism or another neurodevelopmental disorder.
Irva Hertz-Picciotto, a professor of public health services, and Paula Krakowiak MS, a PhD candidate at the MIND Institute at the University of California Davis, and colleagues compared the medical histories of 315 typically developing children to those of 517 children with autism and 172 children with other developmental disorders enrolled in the CHARGE (Childhood Autism Risks from Genetic and the Environment) study. The team also looked at measures of intellectual capacity using the Mullen Scales of Early Learning (MSEL) and the Vineland Adaptive Behavior Scales (VABS), which assessed cognitive and adaptive development, respectively.
“This study was investigating environmental conditions that could affect the developing child during the gestational period,” said Dr. Hertz-Picciotto, senior author of the study. “Usually when you think of environment you think of pollution or chemicals, but environment is very broad. Anything that is not genetic, we consider environmental – so this can include infections, diet, and nutrition. It also includes the health of the mother, because while the fetus is developing, that’s the environment that it’s in.”
The researchers found that when mothers were obese during their pregnancies, their children had nearly a 70% increased risk of having autism. When the mother was either obese or had diabetes, the children had double the risk of other neurodevelopmental delays as well. Maternal hypertension alone was not related to either outcome.
Even when clinical autism or developmental delays were not present, the team found that there is a “general dampening of how the brain is developing,” and the children were still more likely to be behind in their classes.
Krakowiak suggests that these metabolic conditions during pregnancy may impact the baby’s brain development one of two ways. First, the inflammatory proteins that are produced by the mom’s fat cells are also involved in normal brain development. “When the level of those immunological markers is higher or lower than the normal range it might affect how the brain develops in an adverse way,” she says. “And at least one type has been shown to be able to cross over the placenta to the fetus.”
Additionally, the higher levels of blood glucose could negatively impact the developing brain since maternal glucose can also cross the placenta. Higher levels of glucose cause the baby to grow faster and require more oxygen. If an adequate amount is not provided (intrauterine tissue hypoxia), that would also cause development problems. Poorly regulated maternal glucose can also result in iron deficiency which also harms the baby’s brain.
More research is needed to confirm the results as it is unclear whether diabetes or obesity is actually impacting the growth of the fetus, but it’s always possible that these women have something else in common, said Krakowiak. But, “we’re seeing a rise in the rates of obesity and diabetes as well as a rise in autism,” and this could be more than just a coincidence.
The Centers for Disease Control and Prevention (CDC) state that more than 60% of women of childbearing age are overweight and more than 31% are obese. Obesity during pregnancy affects one in five women. Recently announced statistics for autism estimate that about one in every 88 children has an autism spectrum disorder (ASD) and one in every 83 has another developmental delay.
However, “The causes of autism are multi-factorial, there isn’t going to be one umbrella cause,” reminds Dr. Hertz-Piciotto. “Not every obese mom has a child who develops autism, so it’s probably in combination with other factors. But we do have a lot of adaptive mechanisms, so if you take away one possible cause, maybe the baby’s body is able to handle it.”
Until researchers know more, obese moms might want to take the new findings as another reason to lose weight, Krakowiak said. “It doesn’t hurt anybody to lose weight and it comes with other benefits to the mom. So losing weight not only will help you, but it also might potentially help your child to be healthier.”
Krakowiak P, et al "Maternal metabolic conditions and risk for autism and other neurodevelopmental disorders"Pediatrics 2012; DOI: 10.1542/peds.2011-2583.