Risk Factors for Ectopic Pregnancy in Women With Symptomatic First-Trimester Pregnancies

Abstract

Approximately one in 50 pregnancies in the United States is ectopic, and the incidence of ectopic pregnancy (EP) reportedly has increased 6-fold over the past 25 years. Early diagnosis and appropriate outpatient care clearly limit morbidity and mortality from EP as well as helping to preserve future fertility. This study is the first to associate both historical variables and symptoms with the presence of EP in women who present in the first trimester with pain and/or bleeding but in whom the diagnosis is not readily apparent. A total of 2026 such women, seen at a single center in the years 1990 through 1999, were evaluated. EP was diagnosed in 367 patients, ongoing intrauterine pregnancy in 467, and spontaneous abortion (SAB) in 1192. Case patients were slightly older than controls in this largely black study cohort. A large number of possible confounding factors were adjusted for, including age, voluntary interruption of pregnancy in the past, the number of ectopic gestations, a history of pelvic inflammatory disease (PID), parity, moderate to severe bleeding at presentation, pain as the presenting symptom, and the initial level of human chorionic gonadotropin (hCG). A history of EP was positively associated with current EP as were an initial hCG level exceeding 500 mIU/mL, parity of one, past hospitalization for PID, and presentation with either pain or moderate to severe bleeding. Age less than 25 and a history of voluntarily interrupting pregnancy both were negatively associated with EP. Putative risk factors for EP that were not significant factors in the present study included gravidity, previous SAB, previous live births, the past use of an intrauterine device, previous pelvic surgery or cesarean section, and either a history of or current cervical infection with chlamydia and/or gonorrhea. If the risk factors for EP identified in this study do have high predictive value, they may aid the timely diagnosis of this condition, permit medical treatment, lower morbidity and mortality, preserve fertility, and lessen healthcare costs.