The influence of demographic change and cumulative risk of pelvic inflammatory disease on the incidence of ectopic pregnancy.

A retrospective study was carried out to determine the recent epidemiology of ectopic pregnancy in England between the biennial years 1988/9 and 1992/3. The number of ectopic pregnancy cases were combined with numbers of conceptions and the rates analysed for trend over time. The incidence of ectopic pregnancy rose significantly (P = 0.05) over this period. However, this could be entirely explained by increasing numbers of births in older women and a highly significant positive association was found between risk of ectopic pregnancy and maternal age (P < 0.0001). Over the study period the incidence of ectopic pregnancy in women aged 40 years or more was over 14 times that observed in those under 16 years of age. It is suggested that this reflects cumulative risk of acquiring pelvic inflammatory disease. The surveillance of ectopic pregnancy provides a useful indicator of the level of reproductive morbidity in women.