Laboratory experiments have found that vanillin, a flavouring chemical commonly used at high concentrations in e-cigarettes, may disrupt normal embryonic development in pregnant women who use these products.
Researchers studied the effects of the flavouring compound vanillin in test tubes, as testing the chemical directly on human embryos in pregnant women would be unethical.
The human embryonic stem cells used in the experiments resemble cells found in human embryos during the third week of pregnancy and have the ability to develop into any type of cell.
When the researchers exposed the cells to microscopic amounts of vanillin, they found that so-called micromolar concentrations tended to kill the cells, while nanomolar concentrations caused the cells to lose their ability to develop into different cell types.
Dr Prue Talbot, who led the study at the University of California, Riverside, said: “These changes could be extremely serious and could interfere with normal embryonic development.”
The membranes of embryonic cells are known to contain a protein called TRPV4, which interacts with vanillin. When the researchers disrupted the function of this protein, vanillin’s effects on the stem cells were also blocked, leading them to conclude that the protein was responsible for the flavouring compound’s effects on the cells.
The researchers cautioned that findings from test-tube experiments do not necessarily mean that the same effects occur in women and their embryos.
Nevertheless, the study could help explain why e-cigarette use has been associated with difficulty conceiving and miscarriage among women.
Talbot said: “Women do not necessarily know what chemicals are present in e-cigarette products, and our findings suggest that they should exercise caution and that doctors should advise them not to use e-cigarettes during pregnancy, particularly if they are having difficulty conceiving or are at risk of miscarriage.”
