Contribution of psychopathology, psychosocial problems and substance use to urban and rural differences in birth outcomes

Background: Urban residence contributes to disparities in preterm birth (PTB) and birth weight. As urban and rural pregnant populations differ in individual psychopathological, psychosocial and substance use (PPS) risks, we examined the extent to which PTB and birth weight depend on the (accumulative) effect of PPS risk factors and on demographic variation. Methods: Follow-up study from 2010 to 2012 among 689 urban and 348 rural pregnant women. Urbanity was based on the population density per ZIP code. Women completed the validated Mind2Care instrument questionnaire, which includes the Edinburgh Depression Scale, and demographic, obstetric and PPS questions. Pregnancy outcomes were extracted from medical records. With regression analyses we assessed crude and adjusted associations between residence and birth outcomes, adjusted for available confounding or mediating factors. Results: PTB was significantly associated with segregation, maternal age (<25 and ≥ 35 years old), primiparity, smoking during pregnancy and the accumulation of risks, but not with residence (urban, 4%; rural, 7%; P = 0.16). Mean birth weight was significantly lower for urban babies (crude β : −174; P < 0.001). Adjusting for potential confounders and mediators, non-Western ethnicity, parity and smoking during pregnancy significantly decreased birth weight besides residence. The accumulative effect of PPS risk factors significantly decreased birth weight ( β : −58 g per risk factor; P < 0.001). Conclusion: PTB was not associated with residence. The lower birth weight of urban babies remains significant after adjusting for urban risks, such as non-Western ethnicity and the PPS risk factor smoking. The accumulation of multiple (moderate) PPS risks accounts partly for the urban effect.