Chlamydia infection in men is linked to infertility, say Swedish researchers in the May issue of the journal Human Reproduction, who have found that infection in men appears to lessen the chance of their partners becoming pregnant.
In a study of 244 couples attending a fertility clinic, the researchers, from Umea University Hospital and the Scandinavian Fertility Centre in Gothenburg, Sweden, tested for chlamydia antibodies. For those couples where one partner was positive, they also tested for chlamydia DNA in both. The couples were then followed up for an average of 37 months and their pregnancy rates were compared with a control group of women who got pregnant without fertility treatment.
The research team found that pregnancy rates were lower in couples where the man carried IgG (immunoglobulin G) antibodies specific for the bacteria that causes chlamydia, which act as 'markers' of previous or persistent infection. IgG antibodies were present in nearly a quarter of the infertile women and one fifth of the infertile men. In comparison, only 15.6 per cent of the control group carried the antibodies. Among infertile couples with IgG antibodies 6.8 per cent of the women and 7.1 per cent of the men carried chlamydia DNA in their urine, suggesting current and active infection. Of the total study group 3.7 per cent tested positive for chlamydia DNA, but this increased to more than 13 per cent in the infertile IgG-positive couples. Antibodies in the women were related to tubal factor infertility (TFI), which affects the fallopian tubes, but antibodies in men were not associated with TFI in their partners. This suggests that, in men, ' there may be alternative or additional mechanisms involved that are reducing fertility', say the researchers, who also conclude that the chance of a couple achieving pregnancy is reduced by one third if the man is IgG-positive.
In August last year the UK's Family Planning Association (FPA) began a campaign to make the government introduce a national opportunistic chlamydia screening programme. The FPA said that it also hoped to raise public awareness of chlamydia, the most common sexually transmitted infection in the UK. At the time, the FPA's figures showed an increase in the rate of infection in young people aged 16-24. If left untreated, chlamydia can cause pelvic inflammatory disease and infertility in women and, the FPA believed, was also likely to cause fertility problems in men. Although it is easily treated with antibiotics, diagnosis of chlamydia is a problem as it is often asymptomatic in up to 50 per cent of men and 90 per cent of women. Now it appears that the FPA have been proved right.
'Our findings show that it is not only women that need to be concerned about contracting chlamydia', said team leader Professor Jan Olofsson, adding 'men need to be aware that this is potentially serious for them as well'. All men and women who attend fertility clinics should be screened for chlamydia, conclude the researchers.