en 27141466 <p>Background: <em>Chlamydia trachomatis</em> is the etiology of most of sexually transmitted diseases. Colonization of <em>C. trachomatis</em> in the genital tract during early gestation has been associated with preterm birth, and preterm premature rupture of the membranes. The role of <em>C. trachomatis</em> on spontaneous abortion has not yet been proved completely. The aim of this study was to evaluate the frequency of <em>C. trachomatis</em> infection among pregnant women and its association with spontaneous abortion.<br /> Methods: This case-control study was conducted from August 2012 until January 2013. Totally, 218 women were included; 109 women with spontaneous abortion with gestation age between 10-20 weeks (cases), and 109 women with normal pregnancy with gestation age between 20-30 weeks (controls) in Sanandaj, Iran. DNA was extracted from endocervical swabs and a PCR test was conducted for detection of <em>C. trachomatis</em> infection in women using specific primers. Independent T-test and Chi-square were used for comparison of quantitative and qualitative variables, respectively, and p&lt;0.05 was considered significant.<br /> Results: The total prevalence of <em>C. trachomatis</em> infection was 38(17.43%) in endocervical swabs of women. However, the number of cases with <em>C. trachomatis</em> infections was 25 out of 109(22.9%) in the case group and 13 out of 109(11.9%) in control group, respectively. Association between chlamydia infection and spontaneous abortion was statistically significant (OR=2.198, CI 95%: 1.058-4.56).<br /> Conclusion: Our study showed that <em>C. trachomatis</em> infection was associated with spontaneous abortion. Thus, screening and treatment of pregnant women may prevent this adverse pregnancy outcome.</p> Chlamydia trachomatis, Genital infection, Miscarriage, Pregnancy, Spontaneous abortion 110 117 https://www.jri.ir/article/647 https://www.jri.ir/documents/fullpaper/en/647.pdf AmjadAhmadiCellular and Molecular Research Center, Kurdistan University of Medical Sciences, Sanandaj, Iran1487MazaherKhodabandehlooCellular and Molecular Research Center, Kurdistan University of Medical Sciences, Sanandaj, Iranmazaher-kh@muk.ac.ir1488RashidRamazanzadehCellular and Molecular Research Center, Kurdistan University of Medical Sciences, Sanandaj, Iran1489FaribaFarhadifarDepartment of Obstetrics and Gynecology, Social Determinant of Health Research Center, Sanandaj, Iran1490DaemRoshaniSocial Determinants of Health Research Center, Kurdistan University of Medical Sciences, Sanandaj, Iran1491EbrahimGhaderiDepartment of Epidemiology and Biostatistics, Faculty of Medicine, Kurdistan University of Medical Sciences, Sanandaj, Iran1492NiloofarFarhangiBe’sat Hospital, Faculty of Medicine, Kurdistan University of Medical Sciences, Sanandaj, Iran1493