Vaping in pregnancy increases the risk of having a child with behavioural problems, Scots mums have been warned.
According to new research, exposure to flavoured e-cig chemicals in the womb leads to hyperactive offspring.
Those with nicotine cause even more dramatic changes to a growing foetus' grey matter, warn scientists.
Every year 11,000 babies in Scotland are affected by smoking in pregnancy.
Smoking conventional cigarettes during pregnancy has been linked to autism and ADHD (attention deficit hyperactivity disorder) in children.
And now the latest findings, published in the journal Biology Letters, suggest vaping could also trigger neurological conditions.
Lead author Professor Mathilakath Vijayan said: "Vaping during pregnancy exposes the developing baby's brain to chemicals in the vape.
"Our results suggest flavours have the potential to impact pre-natal brain development."
His team at the University of Calgary, Canada, used a technique called PMR (photomotor response). It causes zebrafish embryos to move under light.
The animal model showed exposure to vaping in the womb altered their behaviour - and dulled sensory perception.
Prof Vijayan said: "We tested the effects of flavoured blue raspberry and cinnamon and unflavored vape liquids with and without nicotine.
"While the unflavored vapes had no impact, the flavoured vapes even without nicotine caused profound behavioural changes which were similar to nicotine alone.
"Vaping during pregnancy exposes the developing baby's brain to chemicals in the vape."
He added: "Flavoured vapes with nicotine caused even more behavioural alterations."
The use of e-cigs during pregnancy has been on the rise, partly due to the perception they are safer than traditional tobacco.
Last year the Royal College of Midwives advised pregnant women to use them to help them quit smoking.
But Prof Vijayan said there is limited information on the health impacts to unborn children.
He said: "With more than 7,000 vape flavours on the market, each having unique profiles of chemicals in the final aerosol, characterising their potential neurotoxicity will be an onerous task."
