Many experts have considered vaping a much safer alternative to smoking, urging people—pregnant people included—to use e-cigarettes instead of real cigarettes; after 15 years on the market, millions of Americans are daily users of vapes or e-cigarettes, which have less toxins than cigarettes but other unstudied chemicals and heating elements. But now, researchers from the University of North Carolina at Chapel Hill have found that the nicotine and chemicals in e-cigarettes can actually make it much harder for an embryo to implant in the uterus, according to a study published today in the Journal of the Endocrine Society. The study also found that vaping while pregnant can trigger lifelong developmental abnormalities in babies.
After exposing mice to e-cigarette vapor for several months, the researchers found the fertility of the females drastically impaired. These effects may be more severe in humans, due to various environmental, health, and genetic factors, according to the researchers.
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“These findings are important because they change our views on the perceived safety of e-cigarettes as alternatives to traditional cigarettes before and during pregnancy,” study author Kathleen Caron, the chair of the department of cell biology and physiology at UNC-CH, said in a statement.
It’s long been clear that smoking tobacco is damaging to conception, pregnant people, and fetuses. Smokers usually have a much harder time conceiving, thanks to a harmful mix of nicotine, cyanide, and carbon monoxide found in cigarette smoke. Smokers with testicles see their sperm counts and motilities drop, and smokers with uteruses’ eggs die off more quickly. (Which is to say nothing of the staggering number of other risks it imposes on pregnant people and fetuses.)
One study from 2019 found that even just e-cigarette flavorings, without the nicotine, could harm testicular function in rats. The UNC-CH report is the first examining how vaping impacts uterine fertility, and the findings are just as bleak.
The UNC-CH research suggests that nicotine, no matter how it’s inhaled, threatens chances of uterine conception and puts fetuses at risk of birth defects. Caron suspects that vaping’s ill effects can also be traced to propylene glycol and vegetable glycerin (PGVG), the base liquids in e-cigarettes. Past evidence found that PGVG may up the amount of nicotine a user inhales, depending on how much of it is in the vape. While there are some early studies on additive flavorings in vapes like the above in rats (think vanilla or cinnamon) they haven’t been closely studied in humans or strictly regulated, as Caron told VICE.
Potential threats to reproductive health are another recent strike against e-cigarettes. Earlier this month, the CDC began identifying vaping as the cause of hundreds of emergency room with a life-threatening lung illness, prompting the center to issue a warning against using e-cigarettes or vaping for young people and pregnant women, as well as adults who don’t use tobacco products. Yesterday, another study revealed that vaping increases infections like the flu.
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