Mothers who smoke during pregnancy have daughters who are more likely to experience miscarriages.
This finding is the conclusion of a intergenerational study which analysed data from over 12,000 women over forty years.
Smoking while pregnant is a modern taboo, but 1 in 10 UK mothers are still known to do so, and previous attempts to understand the effects of maternal smoking on fertility have been inconclusive. In this large-scale study, researchers at University of Aberdeen analysed data from women born before 31 December 1972, obtained from the Aberdeen Maternity and Neonatal Databank.
Even after the researchers adjusted for a woman’s own personal smoking habits, the correlation between her own early-life smoke exposure and miscarriage risk remained if her mother had smoked while pregnant. However, the study confirmed that despite the increased risk of miscarriage, there were ultimately no significant effects on fertility in terms of the number of births. The study was published in the Human Reproduction Open journal.
Dr Sohinee Bhattacharya, a pregnancy expert from the University of Aberdeen and one of the study authors, told the BBC: 'The study did not find a link between mothers' smoking and a decrease in fertility in their daughters...Worryingly the study did find a significant increase in the chances of having a miscarriage among the women whose mothers had smoked when pregnant with them.'
One surprising finding was that women who were exposed to smoke in the womb tended to be more likely to conceive, and conceive earlier, than those whose mothers did not smoke while pregnant. However, these effects became non-significant when the researchers adjusted for factors such as socio-economic status.
The authors point out that one limitation to their study is that they cannot determine when damage from tobacco smoke occurs. Children whose mothers smoke while pregnant are also likely to be exposed to smoke in early childhood.
Dr Bhattacharya concluded: 'More research is needed to confirm the link between fertility and exposure to cigarette smoking in the womb.'