Smoking cigarettes during pregnancy is likely to cause damage to foetal organs, especially to the liver, and may do lasting harm, revealed a study.

The findings, led by researchers from the University of Edinburgh, showed that the potent cocktail of 7,000 chemicals in cigarettes was particularly harmful to the prenatal developing liver cells.The liver plays a major role in regulating metabolism by clearing toxic substances from the body.The study also showed that these chemicals damage livers of male and female foetuses differently. While the male tissue showed liver scarring, the female tissue showed more damage to cell metabolism, the researchers said.

For the study, published in the journal Archives of Toxicology, the team developed a novel way to analyse the effects of maternal smoking on liver tissue using embryonic stem cells."Cigarette smoke is known to have damaging effects on the foetus, yet we lack appropriate tools to study this in a very detailed way. This new approach means that we now have sources of renewable tissue that will enable us to understand the cellular effect of cigarettes on the unborn foetus," said David Hay from the University of Edinburgh.

Scientists used pluripotent stem cells -- non-specialised cells that have the distinctive ability to be able to transform into other cell types -- to build foetal liver tissue.Liver cells were exposed to harmful chemicals found in cigarettes, including specific substances known to circulate in foetuses when mothers smoke.The results revealed that a chemical cocktail -- similar to that found in cigarettes -- harmed foetal liver health more than individual components.