Incidence and risk factors for postnatal mental health-related hospitalisation among Aboriginal and non-Aboriginal women giving birth in the Northern Territory

Abstract

INTRODUCTION: Women are at an increased risk of developing mental health-related conditions during the perinatal period. In Australia, there is limited research on the extent of postnatal mental health-related conditions. This study estimates the incidence of postnatal mental health-related hospitalisation and its associated risk factors in the Northern Territory (NT), with separate analyses for births to Aboriginal and non-Aboriginal women to account for socioeconomic, demographic, and cultural differences. METHODS: A whole-jurisdiction cohort study was conducted for all births to NT resident women from 2002 to 2017 using linked records of births from the NT Perinatal Trends and hospital admissions from the NT Inpatient Activity collection. Modified Poisson regression was used to estimate the effect, as adjusted Incidence Rate Ratios (aIRRs), of various risk factors on the incidence of postnatal mental health-related hospitalisation. RESULTS: The study involved 60,118 mother-birth pairs, including 21,296 (35.4%) births to Aboriginal women. The incidence proportion of any postnatal mental health-related hospitalisation was 2.00% (95% CI:1.81, 2.22) for births to Aboriginal women and 0.85% (95% CI:0.76, 0.95) for births to non-Aboriginal women (P < 0.001). Amongst births to Aboriginal women, the risk factors included mental health-related hospitalisation before pregnancy (aIRR: 3.03; 95% CI: 2.10, 4.39), mental health-related hospitalisation during index pregnancy (aIRR: 5.63; 95% CI: 4.08, 7.76), alcohol use at 1st antenatal care visit (aIRR: 1.78; 95% CI: 1.25, 2.53), obstetric complications (aIRR: 1.63; 95% CI: 1.31, 2.03), five-minute Apgar score < 7 (aIRR: 1.73; 95% CI: 1.24, 2.36), and mother's age under 20 years at birth (aIRR: 1.39; 95% CI: 1.01, 1,89). For births to non-Aboriginal women, risk factors included mental health-related hospitalisation before pregnancy (aIRR: 4.26; 95% CI: 1.88, 9.63), mental health-related hospitalisation during index pregnancy (aIRR: 8.00; 95% CI: 5.24, 12.19), violence during pregnancy (aIRR: 3.50; 95% CI: 1.62, 7.55), smoking during pregnancy (aIRR: 1.92; 95% CI: 1.48, 2.50), labour complications (aIRR: 1.40; 95% CI: 1.13, 1.74), and obstetric complications (aIRR: 1.74; 95% CI: 1.40, 2.18). CONCLUSION: The incidence proportion of all postnatal mental health-related hospitalisations was higher for births to Aboriginal women compared to non-Aboriginal women. Distinct and mostly modifiable risk factors were identified for Aboriginal and non-Aboriginal women that should inform targeted and culturally informed approaches to early intervention and prevention.