Maternal obesity may be an important, but largely-unrecognized, risk factor for cerebral palsy, according to researchers at the University of Michigan and Stockholm’s Karolinska Institute. In a new report published by the Journal of the American Medical Association, an international team of epidemiologists has found that the likelihood of delivering a child with a cerebral palsy disorder appears to increase in step with a mother’s body weight.
Maternal Weight Linked To Cerebral Palsy
Cerebral palsy is a family of neuromuscular disorders that impact the way a person moves. Caused by abnormal brain development or brain damage, cerebral palsy conditions represent the most common cause of childhood motor disability, according to the Centers for Disease Control & Prevention.
Researchers have known for decades that women who are overweight or obese live at an increased risk of experiencing pregnancy and labor-related complications. Among other dangers, maternal obesity is an independent risk factor for obstetric complications, the University of Michigan reports, leading to elevated rates of serious medical problems that arise during labor and delivery. Of particular concern is hypoxic-ischemic encephalopathy, or HIE, in which oxygen deprivation during labor leads to brain damage.
Severe Obesity Increases Risk 200%
HIE is a leading cause of cerebral palsy in infants. The question posed by researchers in Sweden is how maternal obesity fits into this picture. Examining data from 1.42 million pregnancies collected by Sweden’s Medical Birth Register, the team found that, as a mother’s body weight increased, her likelihood of delivering a child subsequently diagnosed with a cerebral palsy disorder increased as well:
- Overweight (BMI between 25 and 29.9) – 22% increased risk
- Obesity 1 (BMI between 30 and 34.9) 28% increased risk
- Obesity 2 (BMI between 35 and 39.9) – 54% increased risk
- Obesity 3 (BMI 40 or higher) – 202% increased risk
However, the relationship between maternal obesity and cerebral palsy is not clear-cut. Nearly 50% of the association observed between a mother’s weight and her child’s diagnosis was mediated by asphyxia-related neonatal complications. In other words, maternal obesity increased the risk that a child would suffer asphyxia, which in turn increased the risk of cerebral palsy.
Rising Obesity Rates Trouble Researchers
The study’s findings may provide crucial evidence as researchers struggle to understand why the rate of cerebral palsy has been increasing, despite significant advances in pre- and post-natal care. Lead author Eduardo Villamor, a Professor of Epidemiology at the University of Michigan, says the findings are particularly worrying in light of the developed world’s rising rates of obesity.
“The number of women with a BMI of 35 or more globally doubled from approximately 50 to 100 million from 2000 through 2010,” Villamor told the Daily Mail. “In the US, approximately half of all pregnant women [are] overweight or obes[e] at the first prenatal visit. Considering the high prevalence of obesity and the continued rise of its most severe forms, the finding that maternal overweight and obesity are related to rates of cerebral palsy in a dose-response manner may have serious public health implications.”
The researchers note, however, that their findings apply only to children who are carried full-term. They did not observe a statistically significant association between the rate of cerebral palsy in premature infants and maternal body weight.