The use and awareness of electronic cigarettes began explosively in mid-2007 in our country. Their usefulness for quitting smoking or as a harm reduction tool, as well as their safety of use, still does not have sufficient scientific evidence. Likewise, there is currently not much scientific evidence on the potential passive exposure to the aerosol emitted by these devices. Currently, in our country, the Department of Health of the Generalitat de Catalunya recommends, as a preventive measure until conclusive studies are available, not to use electronic cigarettes around children and pregnant women. However, there are no studies on passive exposure to electronic cigarettes in pregnant women or on in utero exposure of the fetus or newborn.