Featured on the floors of the 2021 ACOG Annual Clinical and Scientific Meeting, the session titled “Vaping and Pregnancy: The Reproductive Risks of Electronic Cigarette Use” reviews what we currently know—and what we still need to learn—about the effects of vaping on a woman’s fertility and pregnancy outcomes.
Amid the exponential rise in the use of electronic cigarettes (e-cigarettes), the “Vaping and Pregnancy: The Reproductive Risks of Electronic Cigarette Use” session at the 2021 ACOG Annual Clinical and Scientific Meeting explored what we currently know—and what we still need to learn—about the effects of vaping on a woman’s fertility and pregnancy outcomes.
How Vaping Became a Billion-Dollar Industry
Led by Dr. Blair J. Wylie, the session began with some history on e-cigarettes. Also known as vapes or electronic nicotine delivery systems, e-cigarettes are battery-powered devices that heat a reservoir of liquid that typically contains nicotine. Since their introduction in 2003, e-cigarettes have grown in prevalence and popularity.
In fact, there are currently over 400 delivery systems on the market, each with their own modifications that tailor to a vaper’s individual preferences. This feature, along with aggressive marketing campaigns positioning it as a smoking cessation option and a healthy alternative to smoking, have resulted in declines in conventional smoking among youths and a sharp increase in the use of e-cigarettes.
According to data from the 2019 National Youth Tobacco Survey, 27.5 percent of middle or high school students have used e-cigarettes in the past month, and more than one million are using e-cigarettes on most days. And while its popularity is highest among youth, e-cigarette use is still prevalent among patients in their 20s and 30s—during their peak reproductive ages.
Based on a few reports, between 1 and 5 percent of pregnant women use e-cigarettes, but that rate is most likely underreported. Some predictors of e-cigarette use in pregnancy include being Caucasian, receiving less than 12 years of schooling, and having a household income less than $16K/year.
What We Know About Vaping’s Impacts on Fertility
Despite the popularity of e-cigarettes, not much research has been done to investigate the risks associated with them. Some of the potential health impacts include respiratory symptoms like increased cough, wheezing, and phlegm production, cardiac symptoms like increased heart rate and higher blood pressure, and burns, but even less is known about the reproductive risks of e-cigarettes.
Starting with fertility, Dr. Wylie shared a study in which pregnant mice were exposed to e-cigarette vapor for five days a week. This exposure very early in pregnancy impaired implantation and altered RNA expression in integrin, chemokine, and JAK signaling pathways. The study also found that the offspring of prenatally exposed mice exhibited delays in time to implantation and fewer pups per litter.
Turning to human data, an online study recruited 4,586 North American female pregnancy planners and looked at their ability to achieve pregnancy within 12 months. Among the participants, 17 percent reported using e-cigarettes at some point, and 4 percent currently used e-cigarettes.
This data suggested some diminishment of fertility among those participants who used e-cigarettes at some point. And while Dr. Wylie admitted that the rate wasn’t statistically significant, it should give ob-gyns and patients alike pause about whether there could be impacts on early pregnancy and fertility.
What We Know About Vaping’s Impacts on Pregnancy Outcomes
Moving on to pregnancy outcomes, Dr. Wylie quoted an animal study that discovered the following effects of prenatal exposure to e-cigarette aerosol on the offspring:
- Decreased fetal weight and length
- Altered neurodevelopment
- Altered neuroregulatory gene expression
- Increased proinflammatory cytokines in newborn lungs
- Cardiac defects
- Facial clefts
- Deficits in memory, anxiety, and hyperreactivity
Dr. Wylie then moved on to human studies, of which there are two to note. Using data from a large urban maternity hospital in North Ireland, no significant difference in birth outcomes from exclusive e-cigarette users and non-smokers was found among 620 individuals. Specifically, birth weight and prevalence of small for gestational age (SGA) were similar among non-smokers and e-cigarette users while decrements in birth weight and an increased risk of SGA were seen among dual users and conventional cigarette users.
This particular study seems to suggest that e-cigarettes have less of an impact on pregnancy outcomes, but Dr. Wylie cautioned that birth weight is a crude measure of impacts during pregnancy.
The last study Dr. Wylie discussed featured cross-sectional US data from the 2016-2017 Pregnancy Assessment Monitoring System to compare pregnancy outcomes among non-smokers, e-cigarette users, dual users, and conventional cigarette users. Contrary to the previous study, this found that there is some degradation of harm among those who use only e-cigarettes, although it had less of an impact on birth weight than conventional cigarettes.
What We Still Need to Learn About Vaping
The limited data from the above animal studies and epidemiologic cohort studies suggest that e-cigarettes may have negative impacts on both fertility and pregnancy outcomes, but there’s still a lot more to learn. This is especially important to investigate because as Dr. Wylie pointed out, e-cigarettes are viewed as a smoking cessation tool and a healthy alternative to conventional smoking, which may not be the case.
So even if it’s discovered that the negative impacts of e-cigarettes are less severe than conventional smoking, it’s critical to stay aware of the risks and latest research so that ob-gyns can offer patients alternate options for smoking cessation in pregnancy that may be safer.