Is there a need to definitively diagnose the location of a pregnancy of unknown location? The case for "no"

Abstract

The ability to predict the outcome of a pregnancy of unknown location (PUL) has been extensively studied over the past decade. Between 8%-14% of PULs will develop into ectopic pregnancies (EP), and therefore the need to confirm pregnancy location is not without good reason. Strategies to predict EP in the PUL population have included the use of various maternal serum biomarkers and repeat transvaginal ultrasound (TVS) examinations in order to avoid delaying this diagnosis. These follow-up tests are associated with substantial financial cost to the healthcare system, as well as impacting on maternal anxiety. However, the majority of women with a PUL at follow-up will either have an intra-uterine pregnancy or a spontaneously resolving PUL, and therefore represent low-risk PULs. Most of these low-risk PULs do not need intervention and expectant management has been shown to be safe and not associated with adverse outcomes. Therefore we need consider whether the current strategies to determine pregnancy location are indeed essential for women with a PUL, especially when balancing the additional health care burden with the potential increase in maternal morbidity/mortality associated with delay in diagnosis. This beckons the question, "Do we really need to definitively diagnose pregnancy location in women with a PUL?