Scientists knew all along the maternal smoking causes harm to the mother and her child. Now, a new study carried out by Roswell Park Cancer Institute (RPCI) and the University at Buffalo (UB) suggests that even secondhand smoke exposure may cause adverse pregnancy outcomes.
Researchers found that women who never smoked but were exposed to secondhand smoke were at greater risk for fetal loss. While there have been numerous studies linking smoking during pregnancy with miscarriage, stillbirth and tubal ectopic pregnancy, research on the effects of secondhand smoke to pregnancy is limited.
According to the researchers, the study is significant in two ways. First, it considered lifetime exposure to secondhand smoke exposure rather than only during pregnancy or reproductive years, taking into consideration smoke exposure in participants’ childhood and adult years. Second, the comparison group of never-smokers was limited to women without any SHS exposure, resulting to a more accurate control group compared to previous studies.
In addition to these, the new study involved a very large sample – 80,762 women and a comprehensive assessment of their smoking habits.
Historical reproductive data, current and former smoking status, and details about secondhand exposure over lifetime were collected from the Women’s Health Initiative Observational Study. Furthermore, participants came from a broad range of geographic areas and had multiple ethnic, educational and socio-economic backgrounds.
Secondhand smoke may lead to adverse pregnancy outcomes
The researchers found that women with the highest level of secondhand smoke exposure, despite not having smoked their entire life, had greater risk of the three adverse pregnancy outcomes – miscarriage, stillbirth and tubal ectopic pregnancy. In fact, the risk was almost the same with those who consumed more than 100 cigarettes in their lifetime.
The highest levels of lifetime secondhand 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.
“This study offers new information for women regarding the lifetime impact secondhand smoke can have on reproductive outcomes and their ability to successfully bring a pregnancy to full term,” says Andrew Hyland, PhD, Chair of RPCI’s Department of Health Behavior, the lead researcher. “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.”
The new study, which was published online in the journal Tobacco Control, marks a significant step towards clarifying the health risks of secondhand smoke.
These groundbreaking findings emphasized the importance of not just abstaining from tobacco use during pregnancy but also avoiding exposure to secondhand smoke. Pregnant women should make sure that they are living in a smoke-free environment to prevent the onset of any of the three adverse outcomes of cigarette smoke exposure.