The association between rural-urban continuum, maternal education and adverse birth outcomes in Québec, Canada.
Rural relative to urban area and low socioeconomic status (SES) are associated with adverse birth outcomes. Whether a graded association of increasing magnitude is present across the urban-rural continuum, accounting for SES, is unclear. We examined the association between rural-urban continuum, SES and adverse birth outcomes. Singleton births from 1999 to 2003 (n = 356,147) were linked to Québec municipalities ranked on a continuum of 3 urban and 4 rural areas based on population and economic base. Maternal education was used to represent SES. Odds ratios (OR) were calculated for preterm birth (PTB), low birth weight (LBW), and small-for-gestational-age (SGA) birth, accounting for municipality and individual-level covariates. We used stratified analyses to examine interaction between SES and rural-urban continuum. Relative to metropolitan area residence, living in small urban or rural areas was associated with adverse birth outcomes. Living in rural areas was associated with SGA birth (OR 1.11, 95% CI 1.05-1.17) and LBW (OR 1.15, 95% CI 1.05-1.26), and living in small urban areas was associated with PTB (OR 1.14, 95% CI 1.08-1.20). Upon stratification by education, living in remote rural relative to metropolitan areas was associated with adverse birth outcomes among university educated mothers only, and living in small urban areas was associated with adverse birth outcomes among mothers with lesser but not higher education. An SES gradient was present in all rural-urban areas, particularly for SGA birth. Differences in perinatal health exist across the rural-urban continuum, and maternal education has a modifying influence.