• Chlamydia trachomatis;
  • chlamydial heat shock proteins 60 and 10;
  • cohort study;
  • subfertility

Problem:  To assess the association between antibodies to Chlamydia trachomatis heat shock proteins 60 and 10 (Hsp60 and Hsp10) and subfertility in a general population sample.

Method of Study:  A nested case (n = 146)–control (n = 278) study in a population-based birth cohort. Serum immunoglobulin (Ig)G and IgA antibodies against C. trachomatis Hsp60 and Hsp10, explanatory factors, were measured by enzyme immunoassay, using recombinant proteins as antigens. The main outcome variable was subfertility (time to pregnancy ≥12 months).

Results:  The prevalence and medians of serum IgA antibodies to Hsp60 and Hsp10 were significantly higher in the female partners of subfertile couple than in their fertile controls. On the contrary, among male partners of subfertile couple, especially among smokers serum antibody levels to Hsp antigens were lower than in the controls.

Conclusion:  The results indicate a serological association of antibodies to chlamydial Hsp antigens with female subfertility in a population-based sample.