Chlamydia trachomatis infections and the risk of ectopic pregnancy in Khon Kaen women

Aim: To determine the prevalence of Chlamydia trachomatis infection and to evaluate the relation of previous and persistent chlamydial infection to ectopic pregnancy (EP) among women in Khon Kaen, Thailand. Methods: We enrolled 32 EP patients in the case group. Control subjects were 57 women undergoing tubal ligation after normal labor. Serum immunoglobulin (Ig)G and IgA antibodies to C. trachomatis were determined using ELISA. Chlamydial DNA was investigated using polymerase chain reaction. Results: The prevalence of chlamydial DNA in fallopian tube tissue was 34.38% of EP patients whereas none was detected in controls. In cervical cells, however, no significant difference in chlamydial DNA between cases (3.13%) and controls (3.51%) was detected. Serum-specific IgG was found more in the EP group than in the control group (21.88% and 5.26%, respectively; P < 0.05). Serum-specific IgA was detected in 5.26% of the control women but not in the EP group. Analysis by multivariate conditional logistic regression revealed a significant association between EP and the various risk factors. Among these, abortion, previous EP and age at first intercourse <15 years were strong predictors of EP. However, the association between specific IgG and EP became non-significant in this analysis. Conclusions: No strong independent association was shown between chlamydial antibodies and the EP risk in Thai women despite DNA detection in fallopian tube tissue. In contrast, factors including abortion, previous EP, and age at first intercourse <15 years were the significant predictors of EP. Efforts to address these other variables will help more in reducing the EP burden in Thai women compared to eliminating C. trachomatis.