Fetal loss in women exposed to cigarette smoke in-utero

Animal studies have shown meiotic errors in follicles after exposure to cigarette smoke in-utero. Epidemiological studies investigating effects of in-utero smoke exposure on fetal loss in humans show inconclusive results and did not control for extraneous smoke exposure. We aimed to investigate the association between cigarette smoke exposure in-utero and risk of fetal loss, independent of active or second-hand smoking.

We used data from the Avon Longitudinal Study of Parents and Children (ALSPAC) cohort (n = 15,445, April 1991-December 1992, Bristol, England). From obstetric history data and questionnaires completed by the participants we assessed previous fetal loss and whether the participant's mother smoked when pregnant with the participant, smoking habits and second-hand smoking. Fetal loss was defined as miscarriage up to 28 weeks of gestation or stillbirth. We performed logistic regression adjusting for confounding and stratifying for smoke exposure.

In 7033 women in-utero smoke exposure and fetal loss status were known; 2012 were exposed to smoke in-utero; 687 of them (34.1 %) ever had a fetal loss. Ever smokers with exposure in-utero (n = 1182) had higher odds of ever having a fetal loss than ever smokers unexposed in-utero (n = 2354, adjusted OR: 1.26; 95 % CI: 1.08, 1.47, p-value < 0.01 for interaction between ever smoking and in-utero exposure). Evaluation of less common combinations of in-utero and extraneous smoke exposure was hampered by small numbers.

In-utero smoke exposure is associated with increased odds of fetal loss when occurring in combination with active smoking of the participants, compounding the odds of fetal loss.