Fertil Steril. 2015 Dec 14.

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

Cameron KE, Senapati S, Sammel MD, Chung K, Takacs P, Molinaro T and Barnhart KT


Objective: To determine if the pattern of decline in hCG curves can discriminate spontaneous abortion (SAB) from ectopic pregnancy (EP).

Design:Retrospective cohort study.

Setting: University hospitals.

Patient(s): A total of 1,551 women with symptomatic pregnancy of unknown location (PUL) and decreasing hCG values.

Intervention(s): None.

Main outcome measure(s): Percentage change in hCG; days and visits to final diagnosis.

Results: Of the 1,551 women with a PUL and declining hCG, 146 were ultimately diagnosed with EP and 1,405 with 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 (229/1,405) a total of 2,841 person-days and 277 clinical visits. Applying the 7-day cutoff would have saved 9% of the SAB population (126/1,405) a total of 1,294 person-days and 182 clinical visits. These cutoffs were separately validated on a group of 179 EPs collected from three university clinical centers. In that population, each cutoff separately ruled out EP 100% of the time.

Conclusions: The decline in serum hCG is slower in EPs than in 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.

Comment: When one follows a woman after abortion, without being sure if it was a complete abortion, it is advisable to follow hCG levels, if possible. This article gives a good overview of how and when to decide between ectopic pregnancy and complete abortion. (HMV)