What is the excess risk of infertility in women following genital chlamydia infection? A systematic review of the evidence.

Abstract

Objective: To summarise evidence on the attributable risk of infertility following chlamydial infection in women.

Methods: Twelve databases were searched, limited to peer-reviewed literature published from January 1970 until September 2007. Conference abstracts and reference lists from reviews published since 2000 and from key articles were hand-searched. Studies were selected for review if they met the following criteria: (i) the study population comprised females of child-bearing age (defined as 15-45 years) and incorporated a comparison group of women documented as 'chlamydia negative'(ii) the study outcomes included either infertility or successful pregnancy; and, (iii) the study design was one of the following: cohort, randomised controlled trial, 'before and after' studies, screening trials and systematic reviews. Studies were excluded if they described genital infections that either did not include Chlamydia trachomatis or described genital chlamydial co-infection, where no data were available for Chlamydia trachomatis infection alone.

Results: 3349 studies were identified by the search. One study satisfied the inclusion criteria, a longitudinal investigation measuring pregnancy rates in adolescent females with and without current chlamydial infection at baseline. This study reported no significant difference in subsequent pregnancy rates, however, it had serious methodological limitations, which restrict its conclusions.

Conclusions: Our systematic review demonstrates the absence of valid evidence on the attributable risk of post-infective tubal factor infertility following genital chlamydial infection. Our findings contribute empirical data to the growing debate surrounding prior assumptions about the natural history of chlamydial infection in women.