Effects of maternal smoking on offspring reproductive outcomes: an intergenerational study in the North East of Scotland.

study questionHow does exposure to cigarette smoke SUMMARY ANSWER: Women exposed to cigarette smoke WHAT IS ALREADY KNOWN: Existing epidemiological studies have been inconsistent, but generally suggest a small decrease in fertility of women exposed to cigarette smoke STUDY DESIGN SIZE DURATION: This cohort study included all women born prior to 31st December 1972 as recorded in the Aberdeen Maternity and Neonatal Databank. Exposure to maternal cigarette smoking PARTICIPANTS/MATERIALS SETTING

methodsWithin the cohort, 3836 women were exposed to cigarette smoke and 8485 women were not exposed to cigarette smoke MAIN RESULTS AND THE ROLE OF CHANCE: The study did not find a link between exposure to cigarette smoke LIMITATIONS REASONS FOR CAUTION: Although the cohort in this study was large, there were women for whom exposure data was unavailable. Data on the adult circumstances of women who did not record a pregnancy was unavailable, precluding adjustment for their own smoking status or social class. In addition, women who migrated from the area or chose childlessness voluntarily were not included in the study. WIDER IMPLICATIONS OF THE

findingsDespite the wide-ranging harmful effects of cigarette smoke on foetal reproductive development, the effect at a population level remains uncertain. An increased risk of miscarriage in women exposed to cigarette smoke is a potentially important novel finding, which should be investigated further. This study illustrates the lack of consensus on the reproductive effects of STUDY FUNDING/COMPETING INTERESTS: No funding received. No competing interests. TRIAL REGISTRATION NUMBER: N/A.