Social determinants and inequitable maternal and perinatal outcomes in Aotearoa New Zealand

Objectives:
Aotearoa New Zealand has demonstrable maternal and perinatal health inequity. We examined the relationships between adverse outcomes in a total population sample of births and a range of social determinant variables representing barriers to equity.

Methods:
Using the Statistics New Zealand Integrated Data Infrastructure suite of linked administrative data sets, adverse maternal and perinatal outcomes (mortality and severe morbidity) were linked to socio-economic and health variables for 97% of births in New Zealand between 2003 and 2018 (~970,000 births). Variables included housing, economic, health, crime and family circumstances. Logistic regression examined the relationships between adverse outcomes and social determinants, adjusting for demographics (socio-economic deprivation, education, parity, age, rural/urban residence and ethnicity).

Results:
Māori (adjusted odds ratio = 1.21, 95% confidence interval = 1.18–1.23) and Asian women (adjusted odds ratio 1.39, 95% confidence interval = 1.36–1.43) had poorer maternal or perinatal outcomes compared to New Zealand European/European women. High use of emergency department (adjusted odds ratio = 2.68, 95% confidence interval = 2.53–2.84), disability (adjusted odds ratio = 1.98, 95% confidence interval = 1.83–2.14) and lack of engagement with maternity care (adjusted odds ratio = 1.89, 95% confidence interval = 1.84–1.95) had the strongest relationship with poor outcomes.

Conclusion:
Maternal health inequity was strongly associated with a range of socio-economic and health determinants. While some of these factors can be targeted for interventions, the study highlights larger structural and systemic issues that affect maternal and perinatal health.