Madrid: Women who smoke during pregnancy give birth to lighter and smaller babies, says a Spanish study.

The findings were borne out by research conducted by the University of Zaragoza in Spain on 1,216 newly born babies.

Such babies were between 180 and 230 grams thinner than the offspring of non-smoking mothers, which averages 216 grams, the journal Early Human Development reports.

Furthermore, subcutaneous (below the skin) skinfolds, which show the amount of fat, are lower in children born of mothers who smoked, according to a Zaragoza statement.

"Given the scarce bibliography on the subject, we had to assess the impact of tobacco on the body composition of babies born to mothers who smoked during pregnancy," Gerardo Rodriguez from Zaragoza who led the study, told SINC, Spain's public scientific information service.

The experts analysed the newly-born full-term babies with a gestational age of 37 weeks of 1,216 mothers (22.1 percent of whom smoked an average of eight cigarettes daily) at the University Clinical Hospital.

The children of those mothers who had admitted to consuming alcohol or taking illegal drugs during pregnancy were excluded from the study.