Article Text

Download PDFPDF
Is it still important to study if ambient air pollution triggers stillbirth?
  1. Marie Pedersen1,2
  1. 1Department of Public Health, Centre for Epidemiology and Screening, University of Copenhagen, Copenhagen, Denmark
  2. 2The Danish Cancer Society Research Centre, Copenhagen, Denmark
  1. Correspondence to Dr Marie Pedersen, Department of Public Health, Centre for Epidemiology and Screening, University of Copenhagen, Øster Farimagsgade 5, Copenhagen K 1014, Denmark; mp{at}

Statistics from

Request Permissions

If you wish to reuse any or all of this article please use the link below which will take you to the Copyright Clearance Center’s RightsLink service. You will be able to get a quick price and instant permission to reuse the content in many different ways.

Stillbirth, or late fetal death, is defined by the WHO as a child born with no signs of life and a birth weight of 1000 g or more, a gestational age of 28 weeks or more, or a length of 35 cm or more.1 It is estimated that 2.6 million children worldwide were stillborn at 28 weeks or more in 2015, primarily in low-income and middle-income countries.2 Half of the stillbirths occur during labour and congenital abnormalities account for less than 10% of stillbirths.2 Stillbirth is an important, yet poorly understood, adverse outcomes of pregnancy. The large geographical variation suggests that the majority of stillbirths are preventable.

In this issue of Occupational and Environmental Medicine, Siddika et al3 reviewed 13 original epidemiological studies that addressed the question of whether maternal exposure to ambient air pollution triggers stillbirth. They conducted a meta-analysis to summarise the existing evidence, and reported evidence of an association between exposure to ambient air pollution and elevated risk for stillbirth. A 4 μg/m3 increase in exposure to particulate matter (PM) with a diameter of less than 2.5 μm (PM2.5) during pregnancy was associated with an increased risk of stillbirth (summary OR 1.02, 95% CI 1.00 to 1.05; 17 033 cases).3 Differences in design and pollutants assessed precluded all 13 studies to be meta-analysed, and thus their analysis was based on only two or three large register-based studies from the USA or Asia. Exposure to other routinely monitoring air pollutants, including nitrogen dioxide …

View Full Text


  • Funding The Danish Council for Independent Research (grant DFF-4004-00179) supports my work.

  • Competing interests None declared.

  • Provenance and peer review Commissioned; internally peer reviewed.

Linked Articles