Infant and Maternal Outcomes for Women Who Experience Imprisonment in Ontario, Canada: A Retrospective Cohort Study

OBJECTIVE: To describe the population-level risk of infant and maternal outcomes for women who experience imprisonment and compare outcomes with the general population. METHODS: We conducted a retrospective cohort study. We used linked correctional and health data for women released from provincial prisons in 2010. We defined three exposure groups for Ontario singleton deliveries from 2005-2015: deliveries to women who were in prison during pregnancy but not necessarily for delivery, prison pregnancies; deliveries to women who had been in prison but not while pregnant, prison controls; and general population deliveries. We compared groups using generalized estimating equations. Primary outcomes were preterm birth, low birth weight, and small for gestational age birth weight. Secondary outcomes included NICU admission, neonatal abstinence syndrome, placental abruption, and preterm prelabour rupture of membranes. RESULTS: In prison pregnancies (n = 544) and prison controls (n = 2156), respectively, preterm birth risk was 15.5% and 12.5%, low birth weight risk was 13.0% and 11.6%, and small for gestational age birth weight risk was 18.1% and 19.2%. Adjusted for maternal age and parity and compared with general population deliveries (N = 1 284 949), odds ratios were increased for prison pregnancies and prison controls, respectively, at 2.7 (95% CI 2.2-3.4) and 2.1 (95% CI 1.9-2.4) for preterm birth, 3.1 (95% CI 2.4-3.9) and 2.7 (95% CI 2.3-3.1) for low birth weight, and 1.6 (95% CI 1.3-2.1) and 1.8 (95% CI 1.6-2.0) for small for gestational age birth weight. CONCLUSION: There is an increased risk of adverse infant outcomes in women who experience imprisonment compared with the general population, whether they are in prison during pregnancy or not.