Researchers in Finland found signs of heavy nicotine exposure in a mother's blood were associated with an increased likelihood of schizophrenia in their kids.
They analysed data on 1,000 schizophrenia patients and matched their birth and health records with non-affected "control" individuals.
Smoking habits from their mums were assessed by looking at levels of a nicotine marker, cotinine, in the blood.
Based on this measurement, a fifth (20%) of mothers of schizophrenia patients were found to have smoked heavily while pregnant, compared with 14.7% of mothers of controls.
"To our knowledge, this is the first biomarker-based study to show a relationship between foetal nicotine exposure and schizophrenia," senior researcher Professor Alan Brown, from the University of Columbia in New York City, said, according to PA.
"These findings underscore the value of ongoing public health education on the potentially debilitating, and largely preventable, consequences that smoking may have on children over time."
Commenting on the study, Jane Munro a midwifery advisor at the Royal College of Midwives, told The Huffington Post UK: "Whilst more research needs to be done in this area, this adds weight to the growing evidence about the potential negative impact of smoking on the mother and her child.
"It is important that midwives have the time to discuss issues such as this with women so that they can offer the level of support and advice needed.
“An Action on Smoking and Health (ASH) report earlier this year showed that around 40% of local authorities in England are cutting budgets to stop smoking services.
"These cuts quite simply are counter-productive to reducing smoking in pregnancy and in the population as a whole."
The NHS advises "protecting your baby from tobacco smoke is one of the best things you can do to give your child a healthy start in life".
Its website states: "Every cigarette you smoke contains over 4,000 chemicals, so smoking when you are pregnant harms your unborn baby.
"Cigarettes can restrict the essential oxygen supply to your baby, so their heart has to beat harder every time you smoke."