ß-hCG and prediction of therapeutic success in ectopic pregnancies treated with methotrexate, results from a prospective observational study

OBJECTIVE: To evaluate the diagnostic accuracy of different beta-human chorionic gonadotrophin (ß-hCG) levels measurement, for predicting success of medical treatment in cases diagnosed as tubal ectopic pregnancy (TEP). DESIGN: Five-year prospective observational study. SETTING: Prenatal Diagnosis Unit, Vall d'Hebron University Hospital - Barcelona. PATIENTS: TEP cases fulfilling criteria for medical treatment with Methotrexate. INTERVENTIONS: ß-hCG levels were measured on d 0, 4 and 7 of treatment. Results were compared by non-parametrical tests. A ROC curve was plotted to define cut-off points. Diagnostic accuracy of the different measurements was evaluated. MAIN OUTCOME MEASURE: Failure of treatment defined as need for surgical treatment or persistence of high ß-HCG levels despite treatment. RESULTS: 126 women were diagnosed as TEP, eligible for medical treatment. There were no differences in parity, age, previous TEP, or adnexal mass size. Success rate was 88%. ß-HCG decreased significantly more, between days 0-7 and 4-7, in the successful cases. LR for success prediction was 6.2 and 7.8 for ß-HCG levels at days 4 and 7 respectively, 4.02 and 2.47 for decrement between days 0-7 (25%) and 4-7 (20%), respectively. CONCLUSION: ß-hCG cutoff values have a potential for predicting a successful medical treatment of TEP.