Acute and Recent Air Pollution Exposure and Cardiovascular Events at Labour and Delivery

Publication Type
Journal Article
Year of Publication
Mannisto, T; Mendola, P; Laughon Grantz, K; Leishear, K; Sundaram, R; Sherman, S; Ying, Q; Liu, D
Start Page
Date Published
Adult; Air pollution; Delivery, Obstetric; electronic health records; Environmental Exposure; Female; Humans; Male; Nitrogen Oxides; Outcome Assessment (Health Care); Ozone; Pregnancy; Pregnancy Complications, Cardiovascular; Risk Assessment; Risk Factors; United States; Xylenes

OBJECTIVE: To study the relationship between acute air pollution exposure and cardiovascular events during labour/delivery.

METHODS: The Consortium on Safe Labor (2002-2008), an observational US cohort with 223,502 singleton deliveries provided electronic medical records. Air pollution exposure was estimated by modified Community Multiscale Air Quality models. Cardiovascular events (cardiac failure/arrest, stroke, myocardial infarcts and other events) were recorded in the hospital discharge records for 687 pregnancies (0.3%). Logistic regression with generalised estimating equations estimated the relationship between cardiovascular events and daily air pollutant levels for delivery day and the 7 days preceding delivery.

RESULTS: Increased odds of cardiovascular events were observed for each IQR increase in exposure to nitric oxides at 5 and 6 days prior to delivery (OR=1.17, 99% CI 1.04 to 1.30 and OR=1.15, 1.03 to 1.28, respectively). High exposure to toxic air pollution species such as ethylbenzene (OR=1.50, 1.08 to 2.09), m-xylene (OR=1.54, 1.11 to 2.13), o-xylene (OR=1.51, 1.09 to 2.09), p-xylene (OR=1.43, 1.03 to 1.99) and toluene (OR=1.42, 1.02 to 1.97) at 5 days prior to delivery were also associated with cardiovascular events. Decreased odds of events were observed with exposure to ozone.

CONCLUSIONS: Air pollution in the days prior to delivery, especially nitrogen oxides and some toxic air pollution species, was associated with increased risk of cardiovascular events during the labour/delivery admission.