Abstract: Objective To identify the changes of the risk factors of ectopic pregnancy(EP) in different periods and explore the effective interventions.Methods A retrospective study was conducted on 568 cases in Beijing Obstetrics and Gynecology Hospital,Capital Medical University which consists of two groups:the early group with 186 cases from Oct.1st 1997 to Sep.30th 1998;while the later group with 382 cases from Oct.1st 2007 to Sep.30th 2008.The risk factors such as age,marriage,pregnancy history,profession,previous medical history and treatment were compared.Results There was no significant difference in average age between the two groups.The rate of women whose age was less than 20 years in the early group was much lower than that in the later group(1.1% vs 4.5%,P=0.006).The rate of unmarried women increased from 21.5% in 1997 to 41.4% in 2007(P=0.000) while the rate of nulliparous women increased from 45.7% in 1997 to 66.8% in 2007(P=0.000).There was no significant difference in pregnancy time and parity between the two groups(P=0.030).The abortion time in the later group was much higher than that in early group.The constituent ratio of worker and farmer apparently decreased while the constituent ratio of cadres,staff and student and other occupation increased by years(P=0.000).The patients with the history of intrauterine device(IUD) in early group was more than that in later group(P=0.000_ and patients with the history of reproductive tract infections(RTIs) and other abdominal surgery were lower than those in the later group(P=0.002,P=0.044).The rate of the history of vaginal lavage,cervical treatment and smoking in the later group were much higher than those in the early group(P=0.000,P=0.009,P=0.002).Conclusion Risk factors for EP altered in the past decade and efficient interventions should be applied accordingly to reduce the EP.

Key words: different period, ectopic pregnancy, risk factor