Ectopic pregnancy incidence in the Republic of Korea in 2009-2015: A population-based cross-sectional study

We estimated the incidence of ectopic pregnancy (EP) and the success rate of expectant management of EP in South Korea. We analyzed data from 2009 to 2015 using the Health Insurance Review and Assessment Service National Inpatient Sample (HIRA-NIS) database. EP was identified by diagnostic codes, and strict EP was identified by both diagnostic codes and treatment codes. From 2009 to 2015, 369,701 cases of EP, abortion, or delivery were extracted from a total of 4,476,495 women. Of the total pregnancies, 8,556 cases were EPs. The incidence of EP was 34.1 +/- 0.7 per 1,000 pregnancies and the incidence of strict EP was 17.3 +/- 0.3 per 1,000 pregnancies. Among women aged 25-44 years, age was associated with a higher incidence of EP (odds ratio [OR]: 1.13; 95% confidence interval [CI]: 1.06, 1.19; P < 0.01). The incidence rates of EP (OR: 0.99; 95% CI: 0.97, 1.01; P = 0.51) did not significantly differ by year. The incidence of EP in Korea was 17.3 +/- 0.3 per 1,000 pregnancies, and almost did not change over 7 years. About 50% of EPs were treated without surgery or methotrexate. This study provides an important reference for the treatment of EP.