Incidence of ectopic pregnancy and sexually transmitted disease in the Canadian Central Arctic.

A retrospective review of all medical evacuations from 1987-1994 of women in the Keewatin District of the Canadian Central Arctic was undertaken to determine the incidence of ectopic pregnancy. The incidence of N. gonorrhoeae and C. trachomatis as major risk factors for ectopic pregnancy was also determined. The average annual incidence of ectopic pregnancy in the Keewatin over the study period was 178/100,000 women age 15-44 years, or 9.6/1,000 reported pregnancies; for Southern Canada the corresponding average annual incidence is 118.3/100,000 women age 15-44 years, or 15.7/1,000 reported pregnancies. The high general fertility rate in the Keewatin (189/1,000 population) accounts for the difference in ectopic pregnancy rates expressed per population versus per pregnancy. The average annual incidence of gonorrhea and chlamydia infection were 1,444 and 3,695/100,000 population, respectively; these rates were 27- and 22-fold higher than those seen in the general Canadian population. The incidence of chlamydia was particularly high (16,194/100,000) in women age 15-24 years. Despite the high incidence of gonorrhea and chlamydia in the Keewatin, the rate of ectopic pregnancy expressed per 1,000 pregnancies is comparable to that seen in Southern Canada. Possible differences between populations in the determinants of tubal damage, including time from exposure to infection to pregnancy, host immunity and bacterial virulence, may account for this observation.