Canada and the US have among the highest rates of family separation through child protection systems (CPS) in the world [1], with an inequitable impact on Indigenous and Black families [2], [3], [4], [5], [6]. These inequities reflect historical and ongoing colonization and structural racism that have long subjected Indigenous and Black families to systematic deprivation, surveillance and forced family separation [3], [7], [8]. Infants comprise the highest proportion of young people removed from their parents by CPS, representing nearly 14% of all children removed in Canada [9] and 20% in the US [10], while also being least likely to reunify with their parents [11], [12], [13]. Reporting to CPS in the prenatal and neonatal period is a common pathway to CPS involvement in infancy and is frequently associated with prenatal or neonatal substance exposure [14], [15]. CPS referrals during this period however have been shown to unevenly burden specific ethnoracial groups. For example, recent research in Canada shows that Indigenous newborns who are First Nations were more than 6 times as likely to be investigated by CPS following a positive toxicology screen than non-Indigenous newborns [12], while one study in the US found that Black newborns were more than 4 times as likely to be reported to CPS at delivery than White newborns with a similar toxicology results [13]. Despite these ethnoracial inequities in newborn reporting, regional and national data on the rate of newborn removal and out-of-home placement, as well as comprehensive assessments of newborn-specific health outcomes following these interventions are lacking.

In Canada, the US, and several other jurisdictions, government-mandated requirements demand that CPS agencies routinely collect data on children receiving protection or services [16]. These case-level data are often aggregated at the regional and/or national-levels and provide the “best available” gold standard for tracking CPS contact and system performance measures. One notable limitation of these data however is that by virtue of being case-level data they cannot be used to track outcomes of child wellbeing at the population-level. To address this data gap hospital records have recently been used to track population-level incidence of alleged maltreatment via categorizing specific illnesses and injuries in patients, offering a data source to conduct population-based analyses previously hindered by the scope of available CPS data [17], [18]. Some of the studies have also used hospital discharge data as a source for identifying newborns discharged to CPS from hospital after birth [19], [20], [21]. These discharge dispositions from birth hospitalization records identify the destination to which the patient is discharged and include a code capturing discharges to social services. Owing to the paucity of data on newborn discharge to CPS from hospitals, these discharge dispositions have the potential to provide a valuable metric of measuring population-level incidence of this outcome.

To date no published studies have examined completeness of hospital codes capturing newborn discharge to CPS, and the validity of these in research at a population level is unknown. To understand the usefulness of discharge codes to identify newborn removals by CPS, we compared them with the presumed gold standard of legal custody status obtained from CPS records in the overall Manitoba population and stratified by First Nations status of the birthing parent.