What is the excess risk of infertility in women after genital chlamydia infection? A systematic review of the evidence
- 1Health Protection Scotland, Glasgow, UK
- 2MRC Social and Public Health Sciences Unit, Glasgow, UK
- 3Community Based Sciences Division, University of Glasgow, Public Health and Health Policy Section, Glasgow, UK
- 4Community Based Sciences Division, University of Glasgow, General Practice and Primary Care Section, Glasgow, UK
- Dr L A Wallace, Health Protection Scotland, Clifton House, Clifton Place, Glasgow, G3 7LN, UK;
- Accepted 15 November 2007
- Published Online First 30 November 2007
Objective: To summarise evidence on the attributable risk of infertility after chlamydial infection in women.
Methods: Twelve databases were searched, limited to peer-reviewed literature published from January 1970 to 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: (1) the study population comprised women of child-bearing age (defined as 15–45 years) and incorporated a comparison group of women documented as “chlamydia negative”; (2) the study outcomes included either infertility or successful pregnancy; and (3) the study design was one of the following: cohort, randomised controlled trial, “before and after” study, screening trial and systematic review. Studies were excluded if they described genital infections that either did not include Chlamydia trachomatis or described genital chlamydial co-infection, in which no data were available for C 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 women with and without current chlamydial infection at baseline. That study reported no significant difference in subsequent pregnancy rates; however, it had serious methodological limitations, which restricted its conclusions.
Conclusions: This systematic review demonstrates the absence of valid evidence on the attributable risk of post-infective tubal factor infertility after genital chlamydial infection. The findings contribute empirical data to the growing debate surrounding previous assumptions about the natural history of chlamydial infection in women.
Contributions: AS, GH, MR, PW and DJG designed the study, obtained funding and provided comments on the review protocol. LAW performed the systematic review with AS in a supervisory role and as second reviewer. LAW, AS and DJG drafted the manuscript and all authors contributed to manuscript revisions. LAW and AS prepared the final paper.
Funding: The systematic review was funded by the West of Scotland Primary Care Sexual Health Research and Development Fund, project ID 03SH05. AS is partly funded by the Chief Scientist Office of the Scottish Executive Department of Health. PW is funded by a primary care research career award from the Scottish Executive Chief Scientist Office. The researchers were wholly independent from the funders of the study.
Competing interests: None.