Following declining human chorionic gonadotropin values in pregnancies of unknown location: when is it safe to stop?

Abstract

Objective To determine if the pattern of decline in human chorionic gonadotropin (hCG) curves can discriminate spontaneous abortion from ectopic pregnancies (EP). Design Retrospective cohort study Setting Three university hospitals Patients One thousand five hundred fifty one women with symptomatic pregnancy of unknown location and decreasing hCG values Intervention None Main Outcome Measures Percent change in hCG; days and visits to final diagnosis. Results Of the 1551 women with a PUL and declining hCG, 146 were ultimately diagnosed with EP and 1405 with spontaneous abortion (SAB). An 85% hCG drop within 4 days or a 95% hCG drop within 7 days both ruled out an EP 100% of the time. Applying the 4-day cutoff to this population would have saved 16% of the SAB population (229/1405) a total of 2841 person-days and 277 clinical visits. Applying the 7-day cutoff would have saved 9% of the SAB population (126/1405) a total of 1294 person-days and 182 clinical visits. These cut-offs were separately validated on a group of 179 EPs collected from 3 university clinical centers. In this population each cut-off separately ruled out EP 100% of the time. Conclusion The decline in serum hCG is slower in EPs than SAB, and can be used to aid clinicians in the frequency and duration of follow-up. Costs and patient time may be saved by allowing women who meet one of these criteria to be followed less frequently.