Sons worst affected by smoking in pregnancy - study

The sons of women who smoke while pregnant experience more long-lasting side effects than their daughters, according to a new study.

University of Aberdeen researchers looked at data from 500,000 people around the UK to assess genetic links.

They said the results indicated that men born to women who smoked through pregnancy were more likely to die younger if they went on to smoke themselves.

The research team said they hoped the findings might help the medical community develop fresh counselling strategies for smokers.

The team looked at the genetic relationship between mothers and their adult children.

Data from 500,000 individuals across 22 centres in Scotland, England and Wales was used.

They found that, at every stage, male foetuses and adult sons were more affected by maternal smoking during pregnancy than females.

They said this was shown by changes in levels of various genes in male foetal livers as early as 17 weeks into pregnancy, right through to adult males having shorter life expectancy.

However the authors said that if the adult man stopped smoking, or did not smoke at all, they could counter any risks.

The team was led by Prof Paul Fowler, chair in Translational Medical Sciences at the University of Aberdeen.

"We hope our findings will pave the way towards investigating the molecular effects of maternal smoking which will allow the scientific community to uncover the specific mechanisms by which the trait modifies or initiates specific diseases," he said.

"Ultimately, we also hope it helps the medical community to develop even better counselling strategies and campaigns towards smoking cessation."

Mihail Mihov took part in the research as part of his studies for a doctorate.

"Maternal smoking during pregnancy has been linked to many health issues for babies," he said.

"However, we previously had limited knowledge about which processes in the womb are influenced by maternal smoking and how they translate to diminished health later in life.

"Our findings show that maternal smoking impacts baby's health, particularly for males, from as early as the second trimester and this continues throughout adulthood."

Felix Grassmann, professor of epidemiology and biostatistics at the Health and Medical University in Germany, co-led the research.

"Most research has been conducted in cohorts with too few individuals thus lacking statistical power to uncover the rarer associations," he said.

"In this research, we used genetic, biochemistry and medical questionnaire data on more than 500,000 individuals making it one of the biggest studies reported on the effects of maternal smoking during pregnancy."

He added: "In short, we found that when a mother smokes during pregnancy her son's liver is more affected than her daughter's liver.

"This difference and the sex difference in risk of death continues into middle age."

The Action on Smoking (Ash) charity welcomed the research as highlighting the "importance of supporting every woman to have a smoke-free pregnancy".