Determinants of infant mortality for children of women prisoners: a longitudinal linked data study

BACKGROUND: There is limited information on the determinants of infant mortality outcomes for the children of women prisoners. This study aimed to explore determinants of infant mortality for Indigenous and non-Indigenous children, with a specific focus on maternal imprisonment during pregnancy as a risk factor. METHODS: Using linked administrative data we obtained a longitudinal sample of 42,674 infants born in Western Australia between October 1985 and June 2013. Data were analysed by maternal contact with corrective services, including; (i) imprisonment during pregnancy, (ii) imprisonment before (but not during) pregnancy, (iii) imprisonment after birth, (iv) community-based correctional orders (but no imprisonment), and (v) no corrections record. Infant mortality rates were calculated. Univariate and multivariate log-binomial regression was undertaken to identify key demographic and pregnancy-related risk factors for infant mortality. Risk factor prevalence was calculated for infants by maternal corrections history. RESULTS: 430 Indigenous and 116 non-Indigenous infants died aged 0–12 months. For singletons, infant mortality rates were highest in Indigenous infants with mothers imprisoned during pregnancy (32.1 per 1000) and non-Indigenous infants whose mothers were first imprisoned after birth (14.2 per 1000). For all Indigenous children, the strongest determinants of infant mortality were: abruptio placentae and other placental disorders (RR = 2.85; 95%CI 1.46–5.59; p = 0.002), maternal imprisonment during pregnancy (RR = 2.55; 95%CI 1.69–3.86; p < 0.001), and multiple gestation (RR = 2.29; 95% CI1.51–3.46; p < 0.001). Indigenous and non-Indigenous infants with mothers imprisoned at any time, and particularly before or during pregnancy, experienced higher prevalence of key pregnancy risk factors. CONCLUSIONS: This is the first comprehensive study of the determinants of infant mortality for children of women prisoners. Infants with any maternal corrections history, including community-based orders or imprisonment outside of pregnancy, had increased infant mortality. Indigenous infants whose mothers were imprisoned during pregnancy were at particular risk. There was a low incidence of infant death in the non-Indigenous sample which limited the investigation of the impact of the specific aspects of maternal corrections history on infant mortality. Non-Indigenous Infants whose mothers were imprisoned before or during pregnancy experienced higher prevalence of pregnancy risk factors than infants of mothers first imprisoned after birth. ELECTRONIC SUPPLEMENTARY MATERIAL: The online version of this article (10.1186/s12884-018-1840-z) contains supplementary material, which is available to authorized users.