Maternal cell phone use during pregnancy and child behavioral problems in five birth cohorts.

•Largest study to date to use prenatal cell phone use data collected prospectively.•High prenatal cell phone use linked to hyperactivity/inattention problems in child.•No prenatal cell phone use linked to low risk for any behavioral problems in child.•Analysis adjusted for many confounders, but associations cannot be judged causal.•Future research should adjust for parenting style, maternal hyperactivity, and more.