Association between cigarette smoking during pregnancy and gestational diabetes mellitus: a meta-analysis

Aims: Several studies have been carried out to examine the association between cigarette smoking during pregnancy and risk of developing gestational diabetes mellitus (GDM), yet the findings are mixed. Therefore, we aimed to estimate the relationship between cigarette smoking during pregnancy and GDM risk. Material and methods: PubMed, ScienceDirect, and Cochrane Library databases were searched up to December 2017. Studies on cigarette smoking during pregnancy and GDM were retrieved. The pooled odds ratios (ORs) and their 95% confidence intervals (CIs) for highest versus lowest level of cigarette smoking were calculated using a random-effects model. Results: Compared to nonsmoking, the pooled ORs of cigarette smoking during pregnancy were 0.98 (95% CI: 0.88-1.10) for GDM. Specifically, the pooled ORs of light smoking and heavy smoking during pregnancy for GDM were 1.10 (95% CI: 0.97-1.25) and 1.02 (95% CI: 0.67-1.53), respectively. Conclusions: Our findings suggest that there is no significant association between cigarette smoking during pregnancy and risk of GDM.