Researchers already know that secondhand smoke, or passive smoking, is linked to myriad risks, including an increased risk of hearing loss, diabetes, and obesity. Now they have discovered new risks to add to the growing list: the increased risk of ectopic pregnancy, miscarriage, and stillbirth.
The new study points out that while smoking during pregnancy is known to be related to a higher risk of birth complications and miscarriage, more information was needed to determine whether passive smoking by pregnant women has similar effects. The study included over 80,000 women who had been pregnant at least once and gone through menopause.
Some of the women were current smokers (around six percent), some were former smokers, and some had never smoked. The women who had never smoked (or, more specifically, had smoked fewer than 100 cigarettes in their lifetimes), were divided into groups according to their secondhand smoke exposure as children, adults at home, and adults at work.
The study found that women who had been smokers during their reproductive years had a 44% higher risk of stillbirth, a 43% higher risk of ectopic pregnancy, and a 16% higher risk of miscarriage than the women who had never smoked and had not been exposed to secondhand smoke.
This was probably not a huge surprise to anyone, but the really interesting results were found in the group of never-smokers. The ones who had experienced secondhand smoke exposure also had a higher risk of miscarriage, stillbirth, and ectopic pregnancy compared with the ones who had never smoked and had not been exposed to secondhand smoke. In addition, the increase in risk was directly related to the level of secondhand smoke exposure the women had experienced.
The women with the highest levels of secondhand smoke exposure – over ten years either as a child, as an adult at home, or as an adult at work – had an extremely elevated risk of miscarriage, stillbirth, and ectopic pregnancy. The risk of having an ectopic pregnancy was a whopping 61% percent greater than that of women with no cigarette smoke exposure, and they were also 55% more likely to have experienced a stillbirth and 17% more likely to have had a miscarriage.
With many states enacting bans on smoking in public places and places of business in recent years, we are certainly headed in the right direction. However, the new research certainly highlights the need for more progress, especially in the states that still have no bans on smoking in public places whatsoever, in order to further protect women and their future babies from secondhand smoke, which appears to be even more harmful than previously thought.
– Yvonne S. Thornton, M. D., M. P. H