Background: A diagnosis of ectopic pregnancy (EP) is primarily achieved using transvaginal ultrasonography (TVS). Pregnancy of unknown location (PUL) is the term used to categorize a pregnancy in a woman with a positive pregnancy test when no pregnancy has been visualized using TVS. This review appraises current tools for the diagnosis of EP, describes the diagnostic criteria for non-tubal EP and reviews the literature on the clinical management of PUL.
Methods: We performed a targeted search using the PubMed database. All articles published in the English language from January 1984 to March 2013 were screened for eligibility.
Results: Using TVS to diagnose EP is highly sensitive (87-99%) and specific (94-99.9%). Variations exist in the criteria used for ultrasound diagnosis. Studies report that between 5 and 42% of women seen for ultrasound assessment with a positive pregnancy test have a PUL. For PUL, measurements of serum human chorionic gonadotrophin (hCG) and progesterone are used to predict pregnancy viability and therefore give an indication of the risk of an EP. Only 6-20% of PUL are subsequently diagnosed with EP. Non-tubal EPs are relatively uncommon, difficult to diagnose and result in disproportionate morbidity and mortality.
Conclusions: Access to expertise and equipment for high-quality TVS means the majority of women with EP in developed countries can be diagnosed rapidly and accurately. Identifying PUL, which are low risk and therefore requiring less follow-up, finding better serum markers for EP and safely identifying women who do not require intervention for EP are the current diagnostic challenges.
Keywords: ectopic pregnancy; expectant management; prediction models; pregnancy of unknown location; transvaginal ultrasonography.