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. ELECTRONIC SUPPLEMENTARY MATERIAL: The online version of this article (10.1186/s12884-018-1868-0) contains supplementary material, which is available to authorized users.