The influence of acculturation on the risk of stillbirth in migrant women residing in Western Australia

ObjectiveTo investigate the influence of acculturation, demonstrated by age on arrival, length of residence, interpreter use and having an Australian-born partner, on disparities observed in the risk of stillbirth between migrant and Australian-born populations in Western Australia (WA).MethodsA retrospective cohort study using linked administrative health data for all non-Indigenous births in WA from 2005–2013 was performed. Logistic regression analysis was used to estimate odds ratios (OR) and 95% confidence intervals (CI). Adjusted odds ratios (aOR) for stillbirth in migrants from six ethnicities of white, Asian, Indian, African, Māori, and ‘other’, with different levels of acculturation, were compared with Australian-born women using multivariable logistic regression analysis and marital status, maternal age group, socioeconomic status, parity, plurality, previous stillbirth, any medical conditions, any pregnancy complications, sex of baby, and smoking during pregnancy as the covariates.ResultsFrom all births studied, 172,571 (66%) were to Australian-born women and 88,395 (34%) to migrant women. Women from African, Indian and Asian backgrounds who gave birth in the first two years after arrival in Australia experienced the highest risk of stillbirth (aOR 3.32; 95% CI 1.70–6.47, aOR 2.71; 95% CI 1.58–4.65, aOR 1.93; 95% CI 1.21–3.05 respectively) compared with Australian-born women. This association attenuated with an increase in the length of residence in Asian and Indian women, but the risk of stillbirth remained elevated in African women after five years of residence (aOR 1.96 [1.10–3.49]). Interpreter use and an Australian-born partner were associated with 56% and 20% lower odds of stillbirth in migrants (p