24-Hour Compared With 48-Hour β-hCG Follow-up for Patients With Pregnancy of Unknown Location ID 2683407

INTRODUCTION: Patients who are followed with a pregnancy of unknown location (PUL) are generally advised to return for repeat β-hCG level after 48 hours. This study compares the time to final diagnosis for patients who had repeat β-hCG levels 24 versus 48 hours after diagnosis of PUL. METHODS: This was a retrospective cohort study of patients diagnosed with PUL who were recommended to return at 24 versus 48 hours at a single site from 2021 to 2022. We reviewed charts for time to final diagnosis, demographic characteristics, pregnancy history, β-hCG levels, interventions, and whether the patient was lost to follow-up. We compared the time to final diagnosis using Kaplan–Meier curves and log-rank tests between the two cohorts. RESULTS: Over the two-year time period, 61 patients were eligible for inclusion, 18 of whom followed up at 24 hours and 43 of whom followed up at 48 hours. Most patients completed the recommended follow-up (94.4% 24-hour versus 83.7% 48-hour). The median time to final diagnosis was 2 days (interquartile range IQR 1–5 days) for the 24-hour cohort compared to 6 days (IQR 3–13) for the 48-hour cohort ( P =.03). None of the 24-hour group was lost to follow-up compared to 11.6% (n=5) in the 48-hour group. CONCLUSION: We found the time to final diagnosis was shorter in the 24-hour group compared to the 48-hour group. Clinicians may consider 24-hour follow-up for patients at higher risk for ectopic pregnancy or to expedite the time to a final diagnosis.