Passive smoking causes more stillbirths compared to Active Smoking : BMJ

A new study published in the BMJ journal Tobacco Control reveals that secondhand smoke (SHS) or Passive Smoking causes thousands of stillbirths, more than active smoking in developing countries, especially in Asia.

Exposure to secondhand smoke or Passive Smoking during pregnancy increases the risk of congenital malformations, infant stillbirth, respiratory illnesses, and low birth-weight. However, not much is know about the extent of SHS exposure during pregnancy. Kamran Siddiqi, from the University of York's Department of Health Sciences, and colleagues conducted the study to assess the prevalence of SHS exposure in pregnant women in low-income and middle-income countries (LMICs).

The investigators used Demographic and Health Survey data collected between 2008 and 2013 from 30 LMICs. Weighted country-specific prevalence of SHS exposure was then estimated among 37 427 pregnant women. Associations between sociodemographic variables and SHS exposure in pregnant women using pairwise multinomial regression model were explored.

• The prevalence of daily SHS exposure during pregnancy ranged from 6% (95% CI 5% to 7%) (Nigeria) to 73% (95% CI 62% to 81%) (Armenia) and was greater than active tobacco use in pregnancy across all countries studied.


• Being wealthier, maternal employment, higher education, and urban households were associated with lower SHS exposure in full regression models.


• 40% of all pregnant women in Pakistan are exposed to secondhand smoke -- causing approximately 17,000 stillbirths in a year.


• Daily SHS exposure accounted for a greater population attributable fraction of stillbirths than active smoking, ranging from 1% of stillbirths (Nigeria) to 14% (Indonesia).


• In Armenia, Indonesia, Jordan, Bangladesh, and Nepal more than 50% of pregnant women reported exposure to household secondhand smoke.


• In Pakistan, only 1% of stillbirths are attributed to women actively smoking during pregnancy, but for secondhand smoke, the figure is 7%, largely due to the high numbers of pregnant women exposed to tobacco smoke in the home.


• In five of the 30 countries, household secondhand smoke exposure was twice as common as active smoking.