Follow-up and outcomes of patients with a pregnancy of unknown location: A comparison of two prediction models

Background: The time period while delineating the final diagnosis following presentation with a pregnancy of unknown location (PUL) can be an anxious time, as well as being time and resource intensive. Prediction models have been utilised in order to tailor counselling, frame expectations and plan care.Objectives: We aimed to review diagnoses of PUL in our population and assess the value of two prediction models.Study design: We reviewed all 394 PUL diagnoses over a three year period in a tertiary level maternity hospital. We then retrospectively applied the M1 and M6NP models to assess their accuracy when compared to the final diagnosis. Results: PUL comprises of 2.9% (394/13401) of attendances in our unit, requiring 752 scans and 1613 separate blood tests. Just under one in ten women (9.9%, n = 39) presenting with a PUL had a viable pregnancy at discharge, however of the remainder, only 18.0% (n = 83) required medical or surgical treatment for a PUL. The M1 model was more successful at predicting an ectopic pregnancy than the M6NP, with the latter over-predicting viable pregnancies (33.4%, n = 77).Conclusions: We demonstrate that the management of women with a PUL could be stratified through the application of outcome prediction models, having positive results for framing expectations and potentially reducing this resource-intensive diagnosis.