4.9 Secondhand smoke and pregnancy

Show / hide chapter menu

4.1 Background

4.2 What is secondhand smoke?

4.3 What is in secondhand smoke?

4.4 Cardiovascular disease and secondhand smoke

4.5 Lung cancer and secondhand smoke

4.6 Cancers of other sites

4.7 Health effects of secondhand smoke for infants and children

4.8 Effects of secondhand smoke on the respiratory system in adults

4.9 Secondhand smoke and pregnancy

4.10 Secondhand smoke and increased risk of infectious disease

4.11 Secondhand smoke and diabetes

4.12 Population prevalence of exposure to secondhand smoke in the home

4.13 Estimates of morbidity and mortality attributable to secondhand smoke

4.14 Public attitudes to secondhand smoke

Acknowledgments

References

4.9.1 Fertility

There is some evidence associating exposure to secondhand smoke with reduced fertility or fecundity (rate of conception) in women, although confirmatory research is required before these outcomes may be stated with certainty.19 In women undergoing IVF treatment, exposure to secondhand smoke may lead to a reduced chance of successful implantation,53 although this finding should also be considered preliminary.

4.9.2 Low birthweight and preterm delivery

Exposure to secondhand smoke during pregnancy causes a small reduction in birthweight.20 Although the decrement in weight is not as great as that seen in babies of mothers who are active smokers, there is evidence that the effect may be more pronounced in disadvantaged groups of the population,16 whose health is more likely to be already compromised.

Mechanisms for causation of lower birthweight in babies of non-smoking mothers exposed to secondhand smoke are likely to be similar to those that cause lower birthweight in infants of active smokers. Factors contributing to low birthweight may be preterm delivery, intrauterine growth retardation, or a combination of the two. The Californian Environmental Protection Agency report has concluded that secondhand smoke is a cause of preterm delivery, and may cause intrauterine growth retardation.19 The most recent report of the US Surgeon General notes that the evidence for preterm delivery is currently 'suggestive' of causality.20

4.9.3 Lung development in the unborn child

Exposure to secondhand smoke in utero causes changes in foetal lung structure, allergic responses and inflammation.20 Recent research suggests that maternal exposure to secondhand smoke may directly effect the development of the alveoli in the lungs of the unborn child.54

4.9.4 Spontaneous abortion (miscarriage)

Maternal exposure to secondhand smoke is associated with an increased rate of spontaneous abortion in some studies, but further research is needed before this finding can be confirmed.19, 20