Maternal mobile phone use during pregnancy versus early childhood in relation to behavioral problems in preschool-aged children: A prospective cohort study.

Evidence on the effect of maternal mobile phone use on child behavioral development remains inconsistent, particularly regarding the relative importance of the prenatal and early childhood exposure periods. We aimed to examine associations between maternal mobile phone call duration during pregnancy and early childhood and behavioral problems in preschool-aged children. We analyzed data from the Mothers and Children's Environmental Health (MOCEH) prospective birth cohort. Maternal mobile phone use was measured by questionnaire during pregnancy and at ages 3-5 years, and child behavioral problems were assessed using the Korean Child Behavior Checklist (K-CBCL) at ages 4, 5, and 6 years. Maternal daily call duration (minutes/day), used as a proxy indicator of mobile phone use, was calculated from daily call frequency and average duration per call. Associations with behavioral problem scores were estimated using linear mixed-effects models in sub-cohorts with available exposure information for the whole period (n = 780), pregnancy (n = 763), and early childhood (n = 418). Mutually adjusted models accounted for maternal mobile phone use during the other exposure period, with missing information treated as a separate category. Early childhood maternal mobile phone use was significantly associated with higher total (β = 1.37, 95% CI: 0.46-2.28) and externalizing (β = 1.44, 0.54-2.33) problem scores, whereas prenatal use was not. Sex-stratified analyses showed associations for total and externalizing problems in males and internalizing problems in females. These findings suggest that maternal mobile phone use during early childhood, rather than pregnancy, is associated with child behavioral problems, pointing to the caregiving pathways, such as interruptions in parent-child interaction caused by technology use, as a plausible explanation.