Researchers have found that e-cigarette usage may impair fertility and pregnancy outcomes in young women.

Many young and pregnant women are using e-cigarettes as a safer alternative to smoking, but little is known about its effects on fertility and pregnancy outcomes. "We found that e-cigarette usage prior to conception significantly delayed implantation of a fertilized embryo to the uterus, thus delaying and reducing fertility (in mice)," said study author Kathleen Caron from the University of North Carolina.

"We also discovered that e-cigarette usage throughout pregnancy changed the long-term health and metabolism of female offspring - imparting lifelong, second-generation effects on the growing foetus," Caron added. For the study published in the Journal of the Endocrine Society, the researchers used a mouse model to examine whether e-cigarette exposure impairs fertility and offspring health.

After exposure to e-cigarette vapour, female mice showed decreased embryo implantation and a significant delay in the onset of pregnancy. Female offspring exposed to e-cigarettes in utero also failed to gain as much weight as those of control mice. "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," Caron added.

E-cigarettes are driving increases in tobacco product use among youth, researchers noted.