A University of Alberta research team is sending out a vehement warning that vaping is not a safe alternative to smoking during pregnancy.
In a recently published paper in the Journal of Hazardous Materials, the researchers reviewed evidence from studies around the world and concluded that using e-cigarettes during pregnancy is associated with harmful outcomes for both mothers and their babies.
"Our recommendation is very straightforward," says Subhabrata Moitra, assistant professor at the Bagchi School of Public Health at Ahmedabad University in India and former postdoctoral fellow at the U of A. "If a mother is smoking while pregnant, ask her to stop because there is no safe alternative."
Twenty-three studies reported on a total of 924,376 participants, with 7,552 reporting vaping-only use during pregnancy.
The evidence showed that prenatal vaping was associated with 53 per cent higher odds of an adverse outcome for mothers — particularly decreased breastfeeding and reduced prenatal care — when compared with not smoking or vaping during pregnancy.
Vaping during pregnancy was also associated with 53 per cent higher odds of an adverse outcome for newborns — including low birth weight, preterm birth and small size for gestational age — all of which increase the likelihood of problems like high blood pressure, obesity, diabetes and respiratory problems later in life.
"The fetus is exquisitely sensitive to environmental chemicals present in the mother's blood. This can interfere with cell division, an incredibly delicate process," says professor of medicine Paige Lacy. "These are chemicals that are teratogenic, which means they may be tolerated by adults but the fetus cannot tolerate them."
The underlying mechanisms behind these harms are not clear from the research, but e-cigarettes contain hazardous heavy metals such as lead, cadmium and nickel, as well as other additives like polyethylene glycol and diacetyl, an artificial flavouring agent implicated in a non-cancerous lung injury called "popcorn lung."
Some chemicals that are safe to ingest may not be safe when vaporized and inhaled into the lungs, the researchers posit, calling for further study.
Smoking rates have dropped in Canada but an increasing number of Canadians are vaping, especially younger people. According to Statistics Canada, in 2022 about one in five Canadians aged 20 to 24 and one in seven aged 15 to 19 reported vaping in the previous month.
Vaping has been marketed as a tool to quit smoking, and studies have shown that some women believe it is a safe alternative to smoking during pregnancy, but the U of A researchers warn against that perception. They want primary care physicians, women who are planning to get pregnant and those who are already pregnant to hear their message.
They say their findings should inform public health campaigns, e-cigarette advertising and sales regulations, and education programs for health-care providers.
The team's research was funded in part by the Northern Alberta Clinical Trials and Research Centre, the Canadian Institutes of Health Research and Synergy Respiratory and Cardiac Care.
