The influence of acculturation on the risk of preterm birth and low birthweight in migrant women residing in Western Australia.

BACKGROUND: The risk of preterm birth (PTB) and low birthweight (LBW) may change over time the longer that immigrants reside in their adopted countries. We aimed to study the influence of acculturation on the risk of these outcomes in Australia. METHODS: A retrospective cohort study using linked health data for all non-Indigenous births from 2005-2013 in Western Australia was undertaken. Acculturation was assessed through age on arrival, length of residence, interpreter use and having an Australian-born partner. Adjusted odds ratios (aOR) for term-LBW and PTB (all, spontaneous, medically-indicated) were calculated using multivariable logistic regression in migrants from six ethnicities (white, Asian, Indian, African, Maori, and 'other') for different levels of acculturation, compared to the Australian-born population as the reference. RESULTS: The least acculturated migrant women, those from non-white non-Maori ethnic backgrounds who immigrated at age ≥18 years, had an overseas-born partner, lived in Australia for < 5 years and used a paid interpreter, had 58% (aOR 1.58, 95% CI 1.15-2.18) higher the risk of term-LBW and 40% (aOR 0.60, 95% CI 0.45-0.80) lower risk of spontaneous PTB compared to the Australian-born women. The most acculturated migrant women, those from non-white non-Maori ethnic backgrounds who immigrated at age <18 years, had an Australian-born partner, lived in Australia for > 10 years and did not use an interpreter, had similar risk of term-LBW but 43% (aOR 1.43, 95% CI 1.14-1.78) higher risk of spontaneous PTB than the Australian-born women. CONCLUSION: Acculturation is an important factor to consider when providing antenatal care to prevent PTB and LBW in migrants. Acculturation may reduce the risk of term-LBW but, conversely, may increase the risk of spontaneous PTB in migrant women residing in Western Australia. However, the effect may vary by ethnicity and warrants further investigation to fully understand the processes involved.

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

OBJECTIVE: To 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). METHODS: A 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, Maori, 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. RESULTS: From 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<0.05), respectively. CONCLUSIONS: Acculturation is a multidimensional process and may lower the risk of stillbirth through better communication and service utilisation and elevate such risk through increase in prevalence of smoking in pregnancy; the final outcome depends on how these factors are in play in a population. It is noteworthy that in women of African background risk of stillbirth remained elevated for longer periods after immigrating to Australia extending beyond five years. For migrants from Asian and Indian backgrounds, access to services, in the first two years of residence, may be more relevant. Enhanced understanding of barriers to accessing health services and factors influencing and influenced by acculturation may help developing interventions to reduce the burden of stillbirth in identified at-risk groups.

Whole blood gene expression profile associated with spontaneous preterm birth in women with threatened preterm labor.

Threatened preterm labor (TPTL) is defined as persistent premature uterine contractions between 20 and 37 weeks of gestation and is the most common condition that requires hospitalization during pregnancy. Most of these TPTL women continue their pregnancies to term while only an estimated 5% will deliver a premature baby within ten days. The aim of this work was to study differential whole blood gene expression associated with spontaneous preterm birth (sPTB) within 48 hours of hospital admission. Peripheral blood was collected at point of hospital admission from 154 women with TPTL before any medical treatment. Microarrays were utilized to investigate differential whole blood gene expression between TPTL women who did (n = 48) or did not have a sPTB (n = 106) within 48 hours of admission. Total leukocyte and neutrophil counts were significantly higher (35% and 41% respectively) in women who had sPTB than women who did not deliver within 48 hours (p<0.001). Fetal fibronectin (fFN) test was performed on 62 women. There was no difference in the urine, vaginal and placental microbiology and histopathology reports between the two groups of women. There were 469 significant differentially expressed genes (FDR<0.05); 28 differentially expressed genes were chosen for microarray validation using qRT-PCR and 20 out of 28 genes were successfully validated (p<0.05). An optimal random forest classifier model to predict sPTB was achieved using the top nine differentially expressed genes coupled with peripheral clinical blood data (sensitivity 70.8%, specificity 75.5%). These differentially expressed genes may further elucidate the underlying mechanisms of sPTB and pave the way for future systems biology studies to predict sPTB.