More research is urgently needed to assess the relative risks of infertility resulting from Chlamydia infections, according to new guidelines from the British Fertility Society (BFS). The guidelines, published in the journal Human Fertility, show that there is currently a lack of solid evidence for estimating the relative risks of adverse long-term reproductive consequences following Chlamydial infection in both men and women. They also highlight the importance of screening all new patients at fertility clinics for Chlamydial infection.

The British Fertility Society carried out a thorough review of published research to present evidence-based guidelines to help UK fertility clinics in their practice of screening and managing couples with possible Chlamydia infection. However, they found there are several areas where there is a lack of properly controlled studies to allow recommendations to be made.

The guidelines identified three areas where further research is particularly needed:

  • Well-designed prospective studies on both men and women to quantify the risk of adverse reproductive outcomes (such as infertility or semen quality) following Chlamydia infection. Although there is substantial evidence that infection can lead to infertility, there are currently no studies quantifying how big this risk is for men and women and how it differs depending on the length of infection and for the different types of complication encountered. It is very important for doctors to be able to give patients diagnosed with Chlamydia evidence-based information on their subsequent risk of infertility.
  • Randomised controlled trials to investigate whether male fertility, and in particular semen quality and sperm function, are improved following treatment for Chlamydia. There is growing evidence that a current Chlamydia infection can adversely affect both sperm quality and function. However, no study has yet been undertaken to investigate whether treatment improves this.
  • Randomised controlled trials to investigate the best way to manage women undergoing investigation for infertility who show evidence of past Chlamydial infection by blood tests showing antibodies. This result may mean that the patient has had a past Chlamydia infection and may be at high risk of having tubal damage as a cause of their infertility. Further research is needed to identify the optimum assessment and treatment paths for these patients.

Dr Valentine Akande, lead author of the guidelines, said:

“Chlamydia is a common sexually transmitted disease, and if it isn’t treated, infection can have a serious effect on reproductive health. In women, Chlamydia can lead to infertility, ectopic pregnancies and chronic pelvic pain, while in men, there is growing evidence that Chlamydia reduces sperm quality and function. It is very important that all patients presenting to fertility clinics are tested for Chlamydia to allow doctors to treat any infection and assess whether any damage has been caused to their fertility. As doctors, we need to be able to provide our patients with accurate information on their subsequent risk of infertility following Chlamydia infection. The British Fertility Society calls for further research to be carried out to estimate the relative risk of subsequent infertility following a Chlamydia infection in women and also to assess whether male fertility improves following treatment for Chlamydia. Chlamydia can be contracted by both men and women and is often a silent infection which may not produce any symptoms. If you are concerned that you may have contracted Chlamydia, we recommend that you visit your GP or local genitourinary medicine clinic.”

In addition, the guidelines made several recommendations for good practice in fertility clinics including:

  • All women undergoing investigation for infertility should be offered Chlamydia screening, in line with current NICE guidelines.
  • Clinicians should take care to use appropriate tests for assessing Chlamydial infection. The most accurate test currently available is the Nucleic Acid Amplification Test. Serology (testing for antibodies to the Chlamydia virus) may also be used to detect evidence of past Chlamydial infection, but is not useful for identifying current infection.
  • Sexual partners should be advised to be screened and treated following a Chlamydia infection to prevent re-infection and onward transmission.
  • Consideration should be given to screening patients for Chlamydia prior to placing their sperm/eggs or embryos in storage. Laboratory staff should risk-assess their storage system to minimise the likelihood of cross-contamination during storage.

General information

Chlamydia (or Chlamydia trachomatis) is one of the most common sexually transmitted infections worldwide, with an estimated 89 million new cases per year. In 2009, there were 217,570 new Chlamydia diagnoses made in the UK, an increase of 7% from 2008*.Chlamydia infection is most common in under 25 year olds and reported incidence has increased over the past ten years. This may be accounted for by increased testing and more sensitive tests, but may also reflect an increase in risk-taking behaviour.

Chlamydia infections cost the NHS more than £100million per year. Due to this, the NHS in England has set up the National Chlamydia Screening Programme for under 25s (http://www.chlamydiascreening.nhs.uk/).

Notes for editors The guidelines will be published in full in the journal Human Fertility 2010, 13: 115-125. DOI: 10.3109/14647273.2010.513893. (Human Fertility website: http://informahealthcare.com/huf). Human Fertility is the official journal of the British Fertility Society.