Study objective: To identify historical and physical examination findings that are predictive of ectopic pregnancy (EP) in pregnant patients with abdominal pain or bleeding.
Methods: This study was conducted in an urban academic emergency department as a prospective observational study of consecutive patients from August 1, 1991, to August 31, 1992, who had abdominal pain or vaginal bleeding and a positive beta-human chorionic gonadotropin level. Patients were excluded if they had a diagnostic ultrasound during a previous visit, or if the uterine size was larger than 12 weeks by pelvic examination. Data were analyzed using chi2 with a P value less than. 05 identified as significant. Odds ratios were determined for significant variables. A classification and regression tree analysis was then performed using the predictive variables to derive a decision tree.
Results: Four hundred forty-one patients were enrolled, 57 of whom (13%) had an EP. Factors by history that increased the risk of EP included pain that was described as moderate to severe, lateral, or sharp. Pain located in the midline decreased the risk of EP. A history of previous intrauterine device use, infertility, prior pelvic surgery, or tubal ligation were each found to be predictive. On physical examination, the presence of peritoneal signs, cervical motion tenderness, or lateral or bilateral abdominal or pelvic tenderness increased the risk of EP. A uterine size larger than 8 weeks by pelvic examination decreased the risk of EP. Combinations of predictive variables identified subsets of patients with either an increased or decreased frequency of EP, but in no case was a combination identified that would confirm or exclude this diagnosis with a high degree of certainty.
Conclusion: History and physical examination findings predictive of EP were identified. However, no constellation of findings could confirm or exclude this diagnosis with a high degree of reliability.