Estimation of the risk of tubal factor infertility associated with genital chlamydial infection in women: a statistical modelling study

Using a statistical modelling approach, our study aim is to determine reliable age-related estimates of the risk of all-cause tubal factor infertility (TFI) following past or current chlamydial infection in women in Scotland. Using data from several sources, a Markov-Chain Monte Carlo model was used to estimate the age-related risk of TFI given genital chlamydia infection at any time. The analysis is based on the probability of a woman ever having chlamydial infection, ever having TFI and ever having a previous chlamydial infection given a diagnosis of TFI. The model was programmed and evaluated using WinBugs14. By the age 44 years, the overall risk of a woman having at least a single chlamydial infection is estimated at 42.9% (95% credible interval 30.0, 59.0%). The risk of a woman having TFI increased from 0.5% in those aged 16–19 years to 0.8% in those aged 40–44. The overall estimated probability of TFI, based on lifetime infertility, given a past or current chlamydial infection, is relatively consistent across all five age groups from 16–44 years, being 0.9% among those aged 25–29 and 1.4% in those aged 35–39; The estimates were found to be sensitive to the definition of infertility, with the estimate increasing from 1.3% in the youngest age group to 2.8% and 4.5% for 24-month primary infertility and primary or secondary infertility, respectively.