Excessive weight or obesity in a pregnant woman may increase her child’s risk of being born with cerebral palsy, a study reports.
The study, “Association between maternal overweight or obesity and cerebral palsy in children: A meta-analysis” published in the journal PLOS One, determined that a significant link existed between the two, but noted that further research is needed.
Recent studies suggest that maternal obesity or overweight during pregnancy is associated with obstetric complications, namely preterm birth, low birth weight, autism spectrum disorders, and intellectual disability.
Several have also linked excessive maternal weight during pregnancy with an increased risk of cerebral palsy in babies. But two studies failed to show this connection, and no consensus exists.
A team of Chinese researchers analyzed published studies that investigated the link between maternal obesity or overweight and the risk of cerebral palsy at birth, to assess if a correlation was evident and possible factors underlying an association.
The team searched for studies in three databases – Ovid Medline, EMBASE and Web of Science – published before August 2017.
Out of 2,699 potential studies, eight – all cohort (group) and case-control reports – were included in their final analysis, totaling 7.95 million participants.
Four studies measured women body-mass index (BMI) — an indication of excessive, normal or low weight — before pregnancy (one study), during early pregnancy (one study, before 14 weeks of gestation), and three studies that assessed maternal BMI at the hospital and did not mention the testing time.
Normal weight (BMI 18.5–24.9 kg/m2) was used as reference in five studies, a lower normal weight (BMI 18.5–22.9 kg/m2) in one study, and a non-obese (BMI<30 kg/m2) in two studies. Cerebral palsy cases were identified from registry data or medical records.
Results showed that maternal overweight or obesity (BMI>30 kg/m2 and BMI>40 kg/m2) were significantly associated with a cerebral palsy risk in a child.
“Maternal overweight, maternal obesity, and maternal obesity III [BMI>40 kg/m2] were associated with a 29%, 45%, and 125% higher risk of CP [cerebral palsy] in offspring, respectively,” researchers wrote.
Pregnant women who were underweight did not have a significant association.
The strongest link between maternal obesity and cerebral palsy risk was particularly detected in studies performed in the U.S. and in Europe.
Maternal obesity may induce inflammation and affect the fetus’ neurodevelopment through different ways, like placental inflammation or oxidative stress. These alterations “may contribute to maladaptive programming of the fetal brain,” the researchers wrote.
Oxidative stress refers to cellular damage that results from an imbalance in the production of reactive oxygen species (free radicals) and antioxidant defenses.
Other mechanisms may be related to insulin resistance or impaired signaling of certain factors (like the brain-derived neurotrophic factor) that are required for the normal development of the placenta and fetal growth.
“Our pooled analyses provide evidence that maternal obesity and overweight are significantly associated with CP in offspring,” the researchers concluded. “Additional studies are required to further investigate this question by identifying more risk factors.”