Background Chlamydia infection is thought to increase the risk of infertility and ectopic pregnancy. Over the last 10 years in Australia, chlamydia testing and notifications have increased dramatically, particularly in young women. As it is unclear how much increasing notifications reflect a true increase in chlamydia incidence, we sought to investigate rates of hospitalisation for the chlamydia-related sequelae, infertility and ectopic pregnancy in New South Wales (NSW), Australia's largest state with a population of 7 million.
Methods Routine data on hospitalisations for infertility and ectopic pregnancy, perinatal data, and population census data from 2001 to 2008 were used to estimate annual age-specific hospitalisation rates for infertility and ectopic pregnancy in women aged 15 to 44 years for the entire state of New South Wales. Hospital separations occuring within each year belonging to the same woman were linked using probabilistic linkage of identifiers so that multiple admissions by one woman were only counted once.
Results From 2001 to 2008 the number of women hospitalised for infertility increased from 7050 to 9978. The greatest increase was seen in women aged 35 to 44 years, from 6.4 [95% CI 6.2 to 6.6] to 11.2 [10.9 to 11.5] per 1000 population (p trend<0.001). There was no significant change among women aged 15 to 24 years (ptrend=0.3); see Abstract P1-S3.01 figure 1A. For women with ectopic pregnancy overall the number of women hospitalised decreased from 1204 to 1192, a decrease in annual rates from 14.3 [13.5 to 15.1] to 12.6 [11.9 to 13.3] per 1000 births (p trend<0.001) but this decrease was mostly in women aged between 25 to 44 years. There was no appreciable fall in hospitalisations for ectopic pregnancy in women aged 15 to 24 years (13.1 [11.5 to 15.0] to 13.1 [11.4 to 15.0] per 1000 births; ptrend=0.9; see Abstract P1-S3.01 figure 1B).
Conclusions Among women aged 25 to 44 years decreases in hospitalisations for ectopic pregnancy and increases in hospitalisations for infertility were observed. The relationships between chlamydia prevalence, testing and notifications do not appear to be straightforward.