Smokeless tobacco use and reproductive outcomes among women: a systematic review

Abstract

Background: Both smoked and smokeless tobacco use have deleterious effects on most major organ systems including the reproductive system. We conducted a systematic review on smokeless tobacco (SLT) use and reproductive outcomes among women. Methods: We searched Pubmed, ProQuest, Cochrane, Wiley and Emerald databases for studies involving smokeless tobacco use in women with any or a combination of three conditions: infertility, menstrual disorders and pelvic inflammatory disease (PID). Eligibility criteria included English language publications from 1st January 1990 - 31st October 2020. CADIMA software used for filtering the studies and modified SIGN checklist for the quality assessment. The findings are reported as per the PRISMA guidelines. The AXIS and ROBIN E tool were used for assessment of risk of bias. Results: In total, three studies addressed our research question. Two studies addressed infertility (prospective cohort: n=501, cross sectional: n=192) of which, the cross-sectional study compared the mean cotinine levels between those with infertility, menstrual disorders and PID. This study also explored the association between SLT and PID. PID was the most common gynecological complaint. Women with PID had significantly higher urinary cotinine levels = 24.95±12.259) ng/ ml (p=0.0144). Mean urinary cotinine in women with menstrual complaints was 19.32±10.29 ng/ml.  The other study used population-based sampling of 501 couples who attempted pregnancy (enrolled in the LIFE Study).  Results showed that 9% and 2% (n=28) of men used snuff and chewed tobacco respectively. and  few of the women used smokeless tobacco.  Time to pregnancy was shorter among smokeless tobacco users relative to smokers. Conclusions: Available studies exploring associations between SLT and reproductive outcomes are inconclusive due to limitations in the study methodologies. More studies with robust study designs are required from low- and middle-income countries with high prevalence of SLT use.