The Association of Preterm Birth With Maternal Nativity and Length of Residence Among Non-Hispanic Black Women

BACKGROUND: Preterm birth (PTB) is associated with future cardiovascular disease (CVD) risk and disproportionally affects non-Hispanic Black (NHB) women. Limited data exist on the influence of length of US residence on nativity-related disparities in PTB. We examined PTB by maternal nativity (US born vs foreign born) and length of US residence among NHB women. METHODS: We analyzed data from 2699 NHB women (1607 US born; 1092 foreign born) in the Boston Birth Cohort, originally designed as a case-control study. Using multivariable logistic regression, we investigated the association of PTB with maternal nativity and length of US residence. RESULTS: In the total sample, 29.1% of women delivered preterm (31.4% and 25.6% among US born and foreign born, respectively). Compared with foreign born, US-born women were younger (25.8 vs 29.5 years), had higher prevalence of obesity (27.6% vs 19.6%), smoking (20.5% vs 4.9%), alcohol use (13.2% vs 7.4%), and moderate to severe stress (73.5% vs 59.4%) (all P < 0.001). Compared with US-born women, foreign-born women had lower odds of PTB after adjusting for sociodemographic characteristics, alcohol use, stress, parity, smoking, body mass index, chronic hypertension, and diabetes (adjusted odds ratio [aOR], 0.79; 95% confidence interval [CI], 0.65-0.97). Foreign-born NHB women with < 10 years of US residence had 43% lower odds of PTB compared with US-born (aOR, 0.57; 95% CI, 0.43-0.75), whereas those with ≥ 10 years of US residence did not differ significantly from US-born women in their odds of PTB (aOR, 0.76; 95% CI, 0.54-1.07). CONCLUSIONS: The prevalence of CVD risk factors and proportion of women delivering preterm were lower in foreign-born than US-born NHB women. The “foreign-born advantage” was not observed with ≥ 10 years of US residence. Our study highlights the need to intensify public health efforts in exploring and addressing nativity-related disparities in PTB.