Pregnancy complications by overweight and residential area. A prospective study of an urban Norwegian cohort

Background. Health varies in residential areas of different socioeconomic status in the capital of Norway. This study compares risks of pregnancy complications in Oslo according to prevalence of overweight and areas of residency. Methods. Prospective cohort study of 3,677 pregnancies. Pregnancy outcomes were retrieved from medical records after delivery. Statistics were performed by logistic regression analyses. Results. Pregnant women from areas of lower socioeconomic status (Oslo East) had higher prevalence of overweight than women from areas of higher status (Oslo West). Dose–response relationships were found between body mass index and increased risk of pregnancy complications (pre‐eclampsia, gestational hypertension, gestational diabetes mellitus, macrosomia, cesarean deliveries, acute cesarean deliveries, transfer of the newborn to neonatal intensive care unit). Comparing Oslo East with Oslo West the relative risks of pregnancy complications were 1.8 for pre‐eclampsia, 1.6 for gestational diabetes, 1.4 for acute cesarean deliveries, 1.6 for low birth weight (≤2,500 g) and 1.5 for transfer to neonatal intensive care. Adjustment for body mass index did not change the increased risks of pre‐eclampsia, acute cesarean deliveries, low birth weight, or transfer to neonatal intensive care among Oslo East women. Only the increased risk of gestational diabetes could partially be explained by higher body mass index. Conclusions. Residential areas of lower socioeconomic status had higher risk of pregnancy complications. Overweight was a strong independent predictor of pregnancy complications. The higher prevalence of overweight in Oslo East could, however, not explain the increased risk of pregnancy complications.