VAPING could make women infertile by preventing embryos being accepted in the womb.
Smoking e-cigs could also harm the health of the daughters of women who do get pregnant.
It damages their metabolism and puts them at risk of cardiovascular disease and diabetes, tests showed.
The experiments were on mice but the findings may apply to humans, scientists said.
Prof Caron, of the University of North Carolina, said: “We found e-cigarette usage prior to conception significantly delayed implantation of a fertilised embryo to the uterus – thus delaying and reducing fertility.
“We also discovered e-cigarette usage throughout pregnancy changed the long-term health and metabolism of female offspring – imparting lifelong, second-generation effects on the growing foetus.”
“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.”