Ectopic pregnancies: rising incidence rates in Northern California.

In a population of about 300,000 Northern California women aged 15--44, the age-adjusted incidence of ectopic pregnancy rose from 55.5 to 84.2/100,000 women, 1972--1978. The ratio of ectopics to 1,000 deliveries-plus-spontaneous abortions rose from 9.4 to 14.8. The change occurred mainly in women under age 30, and was observed in seven of the eight hospitals in the area. There was no alteration in the frequency of hospitalized pelvic inflammatory disease (PID); salpingitis decreased over the years studied; and tubal sterilization events remained constant at around 0.9 per cent per year of women aged 15--44.