Risk Factors for Ectopic Pregnancy: A Multi-center Case Control Study

Abstract

Background: Ectopic pregnancy (EP) is defined as a pregnancy in which fertilized oocyte implants outside the endometrial cavity. Although there is no known etiology for ectopic pregnancy, some risk factors of EP have been determined. It has been evident that ectopic pregnancy can be of multifactorial origin. This multicenter research aims to study risk factors associated with increased risk of ectopic pregnancy in women living in Kabul. Methods: A multicenter case control study was conducted in five tertiary maternity hospitals located in Kabul, Afghanistan. A total of 457 pregnant women were included in this study. In the case group, women with diagnosed ectopic pregnancy, while in control group women with intrauterine pregnancy were included. For each case in this study, two controls were enrolled. Results: The mean (SD) age of women in case group was 27.9 (6) years while in control group it was 26.4 (5.5) years. This difference was not statistically significant. We found a significant association between history of abortion and EP (Adj. OR=1.57; 95%CI: 1.02, 2.42). Having history of abdominal/pelvic surgery was a risk factor for EP with adjusted OR 1.94 (95%CI: 1.15, 3.30). In this study we found an increasing risk of EP in women of 35 years or older compared to younger women (Crude OR=2.26; p= 0.024). In women reporting prior EP, the chance of its recurrence was increased (Crude OR= 9.64; 95%CI: 1.1, 83.2). No association of gravidity and parity was found with EP incidence. Conclusions: In this study we found a statistically significant association between history of abdominal/pelvic surgery and EP. In addition, history of abortion was suggested as a risk factor for ectopic pregnancy. In case of having a previous EP probability of its recurrence will be increased. Women with advanced age having other potential risk factors will be facing higher risk of EP.