Trends in ectopic pregnancies and use of intrauterine devices in Lombardy, Italy 1979-1983

The frequency of ectopic pregnancies in Lombardy (a region in Northern Italy with a population of about 9 million inhabitants) over the period 1979-1983 was estimated using the Regional Hospital Discharge Registration System, where information is collected on all discharges from public and private hospitals. The ratio of ectopic pregnancies rose from 4.43/1000 pregnancies in 1979 to 4.93/1000 pregnancies in 1982 and flattened off in 1983 (4.78/1000 pregnancies). The frequency of ectopic pregnancies increased with maternal age from 2.30/1000 pregnancies in teenagers to 6.01/1000 pregnancies in women 30-39 years old, but remained constant thereafter (5.84/1000 pregnancies in women aged 40 or older). These trends were consistent with available information on intrauterine device (IUD) sales over the same calendar period. On the basis of a random subsample of the same dataset, we evaluated by means of a case-control approach, the relative risk of ectopic pregnancy in relation to IUD use. Current IUD users had an estimated age-adjusted relative risk of ectopic pregnancy of 3.6 (95% confidence interval = 1.4-8.0) in comparison with an hospital-based control group of non-pregnant women. In etio-pathological terms, the interpretation of this finding is not obvious since it is possible that IUD users are simply less protected than pill, barrier or other traditional method users against ectopic pregnancy. Nonetheless, on a public health scale, the impact of IUD on the incidence of ectopic pregnancy should be evaluated in relative terms of comparison with other methods and their utilisation in different populations.