Acute and recent air pollution exposure and cardiovascular events at labour and delivery

Heart. 2015 Sep;101(18):1491-8. doi: 10.1136/heartjnl-2014-307366. Epub 2015 Jun 23.


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.

Publication types

  • Research Support, N.I.H., Extramural
  • Research Support, Non-U.S. Gov't

MeSH terms

  • Adult
  • Air Pollution* / adverse effects
  • Air Pollution* / analysis
  • Delivery, Obstetric / methods
  • Delivery, Obstetric / mortality
  • Electronic Health Records
  • Environmental Exposure* / adverse effects
  • Environmental Exposure* / analysis
  • Female
  • Humans
  • Male
  • Nitrogen Oxides* / analysis
  • Nitrogen Oxides* / toxicity
  • Outcome Assessment, Health Care
  • Ozone* / analysis
  • Ozone* / toxicity
  • Pregnancy
  • Pregnancy Complications, Cardiovascular* / chemically induced
  • Pregnancy Complications, Cardiovascular* / epidemiology
  • Pregnancy Complications, Cardiovascular* / prevention & control
  • Risk Assessment
  • Risk Factors
  • United States / epidemiology
  • Xylenes* / analysis
  • Xylenes* / toxicity


  • Nitrogen Oxides
  • Xylenes
  • Ozone