Perinatal Substance Use and Factors Associated With Maternal and Neonatal Morbidity and Mortality

Pregnant people who use substances face barriers accessing care. There are limited data on maternal and neonatal health in this population. Our objective was to determine the association of clinical and demographic factors with maternal and neonatal morbidity and mortality among people with perinatal substance use disorder (PSUD). This population-based retrospective cohort study using provincial health administrative data within a publicly funded universal health care setting (British Columbia [BC], Canada) included all dyads with PSUD indicated within the past year of first-prenatal care contact to delivery (2010-2021). Exposures included sociodemographic, pregnancy, and clinical factors. Primary outcomes included maternal and neonatal morbidity. We employed regression models to estimate adjusted odds ratios (aORs) and predicted probabilities. Among 22 856 people with PSUD with 27 637 deliveries, maternal morbidity rate was 1.5 times higher than all BC deliveries and neonatal morbidity and mortality rates were over 2 times higher. Relative to other BC regions, residing in Vancouver Coastal increased maternal morbidity odds (aOR, 1.35; 95% CI, 1.15-1.59). Residing in Interior or Vancouver Island increased neonatal morbidity odds (aOR, 1.16; 95% CI, 1.06-1.26; aOR, 1.10; 95% CI, 1.01-1.21, respectively). Delivery during more recent years increased maternal mortality odds by 11% (aOR, 1.11; 95% CI, 1.00-1.24). People with PSUD had 2 times higher rates of maternal and neonatal morbidity and mortality than provincial rates. Odds of maternal mortality increased 11% annually. Region of residence, SUD type, demographic, and clinical factors were independently associated with maternal and neonatal morbidity. Enhanced care and health surveillance are needed to address disparities in this population.