Preconception Tobacco Smoke Exposures and Miscarriage Among Women Seeking Fertility Care: A Prospective Cohort Study

Background. This preconception cohort study examined associations between active smoking, secondhand smoke (SHS) exposure, and miscarriage among women seeking fertility care. Methods. Women attending a fertility clinic in Louisville, Kentucky were recruited and prospectively followed from 2016-2019. Preconception tobacco smoke exposures were reported and verified with urinary cotinine. Multivariable logistic regression was used to estimate adjusted odds ratios (aORs) and 95% confidence intervals (CIs). Models were adjusted for age, body mass index, method of conception, menstrual cycle regularity, marital status, race and male factor infertility. Results. Of 76 women with known pregnancy outcomes, 14 were active smokers, 18 were nonsmokers with high SHS exposure and 44 were nonsmokers with low SHS exposure. Active smoking (aOR: 4.69; 95% CI: 1.03, 26.6) and spousal smoking (aOR: 6.60; 95% CI: 1.32, 51.5) were associated with increased odds of miscarriage. Among nonsmokers only, women with high SHS exposure had higher odds of miscarriage (aOR: 4.59; 95% CI: 1.16, 21.3) than women with low SHS exposure, and a significant trend was observed between urinary cotinine and odds of miscarriage (P = 0.04). These findings suggest that preconception smoking and high levels of SHS exposure may increase the risk of miscarriage among women seeking fertility care.