Secondhand tobacco smoke exposure is associated with increased risk of failed implantation and reduced IVF success.

<bold>Background: </bold>Infertility and early pregnancy loss are prevalent as is exposure to secondhand tobacco smoke (STS). Previous research has suggested a relationship between STS exposure and early pregnancy loss, but studies have been limited by small study sizes and/or imprecise methods for exposure estimation. IVF allows for the collection of follicular fluid (FF), the fluid surrounding the pre-ovulatory oocyte, which may be a more biologically relevant sample media than urine or serum in studies of early reproduction.<bold>Methods: </bold>In a retrospective analysis of a prospective cohort study, we measured cotinine in FF collected during 3270 IVF treatment cycles from 1909 non-smoking women between 1994 and 2003 to examine the relationship between STS exposure and implantation failure.<bold>Results: </bold>In adjusted models, we found a significant increase in the risk of implantation failure among women exposed to STS compared with those unexposed [odds ratio (OR) = 1.52; 95% confidence interval (CI) = 1.20-1.92; risk ratio (RR) = 1.17; 95% CI = 1.10-1.25]. We also found a significant decrease in the odds for a live birth among STS-exposed women (OR = 0.75; 95% CI = 0.57-0.99; RR = 0.81; 95% CI = 0.66-0.99).<bold>Conclusions: </bold>Female STS exposure, estimated through the measurement of cotinine in FF, is associated with an increased risk of implantation failure and reduced odds of a live birth. [ABSTRACT FROM AUTHOR]