Association of Chlamydia trachomatis infections with preterm delivery; a systematic review and meta-analysis

Background: Premature birth is a primary cause of infant mortality and its etiology varies in different countries. Chlamydia trachomatis (CT) is a common infectious agent transmitted through sexual contact. The purpose of this study is to investigate the connection between CT infections and preterm birth by meta-analysis. Methods: All articles published in literature databases including Google Scholar, PubMed, ISI (Web of Science), Biological Abs, IranMedex, SID, and Scopus were investigated. Twenty-four relevant articles, authored betweenm 1998-2014 were analyzed through a random effects model. Heterogeneity of the studies was evaluated by I-2 index. The relationship between years of data collection, sample size, and CT infections with preterm delivery prevalence was examined by meta-regression. Data were analyzed with R and STATA [Ver. 12]. Results: The overall prevalence of CT infections leading to preterm deliveries was estimated to be 0.13% (CI 95%: 0. 11-0.16). The prevalence of CT infections leading to preterm deliveries were calculated based on the study method including PCR [0.06 (CI 95%: 0.04-0.09)], serology [0.23 (CI 95%: 0.10-0.35)] and culture [0.17 (CI 95%: 0.10-0.24)]. Analysis indicates that women with chlamydia infections were 2.28 more likely to deliver pre-term in comparison with those who were not infected. It can be concluded that chlamydia infections increase the risks of preterm delivery, OR = 2.28 (95% CI: 1.64-3.16). Conclusions: In regard to the results in numerous studies performed on different continents, this meta-analysis showed a clear association between preterm delivery and prior CT colonization.