Second-hand Smoke and Pregnancy: What’s the Risk?

Second-hand smoking is associated with pregnancy loss that includes miscarriage, stillbirth as well as tubal ectopic pregnancy, as reported by a new study from Roswell Park Cancer Institute (RPCI) and the University at Buffalo (UB). The research findings, released online by the journal Tobacco Control, mark an important step to identifying the hazards of secondhand smoke exposure.

Though there has been previously a number of evidence that cigarette smoking when pregnant was related to the three outcomes of foetal loss examined here — spontaneous abortion or miscarriage (loss of a foetus before 20 weeks of gestation), stillbirth (loss of a foetus after 20 or more weeks of gestation) and tubal ectopic pregnancy — this kind of evidence for secondhand smoke (SHS) exposure were limited. This research is important in two ways: One, it takes into account lifetime SHS exposure instead of only during pregnancy or reproductive years, considering smoke exposure in participants’ early years and grownup years. Two, the assessment group of never-smokers was available only in women with no SHS exposure, creating a truer control group compared to earlier studies.

The substantial sample size and extensive evaluation of SHS exposure added strength to the findings. Historical reproductive data, current and former smoking status, and details about SHS exposure over lifespan were gathered from the Women’s Health Initiative Observational Study . This allowed for a research group of 80,762 women.

Women with the very high levels of SHS contact — in spite of not having smoked themselves — had higher estimates of danger for all three unfavourable pregnancy results, and these risks came the possibility observed among women who smoke (women who smoked greater than 100 cigarettes in their lifetime). The highest levels of lifetime SHS exposure were identified by childhood exposure for more than 10 years, adult home contact for over 20 years and adult work exposure for more than 10 years.

“The strength of the study also provides public-health professionals and others with information upon which to base health guidelines about the significant consequences of secondhand smoke.” says the study’s lead investigator, Andrew Hyland, PhD, Chair of RPCI’s Department of Health Behaviour.