Traffic noise exposure and maternal pregnancy complications: A Nordic registry study

Abstract Background Due to urbanisation, the number of residents exposed to high traffic noise levels is increasing. Traffic noise has been associated with an increased risk of ischaemic heart disease and several cardio-metabolic outcomes, with stress and sleep disturbance as potential effect pathways. It is, thus, plausible that traffic noise may have adverse effects on pregnancy outcomes, but the evidence is scarce and inconclusive. The present study aimed to address this gap by investigating whether residential exposure to road and rail traffic noise is associated with maternal pregnancy complications. Methods The study population included all singleton pregnancies from five Nordic metropolitan areas: Copenhagen, Denmark (years 2005-2016); Helsinki, Finland (2004-2014); Oslo, Norway (2005-2014); and Gothenburg and Stockholm, Sweden (2007-2012), total n = 540 439. Data were retrieved from national registers. Road and rail traffic noise levels were modelled at residential addresses. We ran logistic regression analyses separately in each country and combined the results in random-effect meta-analyses. Covariates included individual (age, parity, birth year, marital status, education), area-level (% low-income households in neighbourhood) and address-level (green and blue space, aircraft noise, air pollution) factors. Results In the meta-analyses, a 10 dB higher exposure to road traffic noise during pregnancy was associated with higher odds of gestational diabetes (OR 1.08; 95% CI 1.04-1.12) but not with gestational hypertension (0.95; 0.78-1.16) or mild (0.99; 0.91-1.07) or severe pre-eclampsia (1.00, 0.90-1.11). Rail traffic noise was associated with pregnancy complications in some countries but not in the meta-analyses. Conclusions Exposure to road traffic noise seems to be associated with higher risk of gestational diabetes in Nordic metropolitan areas. For maternal health, road traffic noise abatement is, thus, increasingly important in urban areas. Key messages • Residential road traffic noise was consistently associated with increased odds of gestational diabetes, but not gestational hypertension or pre-eclampsia, in urban Nordic areas. • Road traffic noise, an urban environmental stressor, seems adversely associated with gestational diabetes, which is known to increase the risk of severe pregnancy complications.