This study will examine the link between prescription opioid misuse on risks of maltreatment and foster placement through creation of a statewide birth cohort of mothers enrolled in Medicaid at the time of delivery. Study aims include creating a statewide birth cohort of mother-child pairs enrolled in Medicaid at the time of delivery, and integrating the cohort with child maltreatment and foster care record systems (PA Medicaid Birth Cohort, PMBC). This cohort will be used to document maternal prenatal and postnatal prescription opioid use and misuse rates, and examine the relation to a range of maternal and child risk characteristics to misuse, as well as the effect of prescription opioid and other substance misuse on risks of child maltreatment and foster care placement.