A new study has found that exposure to secondhand smoking increases an expecting woman's chances of miscarrying, stillbirth and tubal ectopic pregnancy.
The findings of the study, conducted by scientists at Roswell Park Cancer Institute (RPCI) and the University at Buffalo (UB), mark a significant step toward clarifying the risks of secondhand smoke exposure.
Study's lead investigator, Andrew Hyland, Chair of RPCI's Department of Health Behavior, said that the study demonstrated that pregnancy outcomes can be correlated with secondhand smoking.
Significantly, women who have never smoked but were exposed to secondhand smoke were at greater risk for fetal loss, Hyland said.
The study is significant in two ways: One, it considered lifetime SHS exposure rather than only during pregnancy or reproductive years, taking into consideration smoke exposure in participants' childhood and adult years.
Two, the comparison group of never-smokers was limited to women without any SHS exposure, producing a truer control group compared to previous studies.
The large sample size and comprehensive assessment of SHS exposure added strength to the findings.
Historical reproductive data, current and former smoking status, and details about SHS exposure over lifetime were collected from the Women's Health Initiative Observational Study. This allowed for a study group of 80,762 women.
Women with the highest levels of SHS exposure - despite never having smoked themselves - had significantly greater estimates of risk for all three adverse pregnancy outcomes, and these risks approached the risk seen among women who smoked more than 100 cigarettes in their lifetime.
The highest levels of lifetime SHS exposure were defined by childhood exposure for longer than 10 years, adult home exposure for more than 20 years and adult work exposure for more than 10 years.
The study is published online in the journal Tobacco Control.
