Pregnancies of unknown location: consensus statement

Abstract

The rate of PULs in different studies ranges from 8 to 31%1-10. The prevalence of PULs is determined by the quality of ultrasound scanning11. The higher the quality of scanning, the better the detection of ectopic pregnancy using ultrasound as a single diagnostic test, which in turn results in fewer women being classified with a PUL. Up to 90% of clinically relevant ectopic pregnancies can be detected at the initial ultrasound scan12-14. The panel believes that most modern units using TVS should maintain PUL rates below 15%. Most PULs are not aggressive and represent either failing intrauterine or ectopic pregnancies which are never visualized using TVS (failing PULs) or intrauterine pregnancies too early to visualize using TVS. Clinically stable women with a PUL should initially be managed expectantly, as expectant management of women with a PUL is safe1-7, 15. There is no consensus about appropriate intervention rates in women with a PUL. Clinical audit should be regularly performed to determine the rate of emergency surgery because of undetected ectopic pregnancies and the rate of unnecessary intervention (negative laparoscopy). The initial serum human chorionic gonadotropin (hCG) level is not predictive of PUL outcome11, 16. The change in serum hCG over time or the hCG ratio (hCG at 48 h/hCG at 0 h) can be used to define failing PULs16, 17. Initial serum progesterone levels <20 nmol/L or a 48-h hCG ratio <0.87, i.e. a serum hCG fall >13% over 48 h, identify those PULs which resolve spontaneously and do not require intervention4, 16. Further studies are required to compare the hCG ratio to serum progesterone as markers of pregnancy failure. Serum progesterone measurements are not reliable in the diagnosis of ectopic pregnancy18. According to a meta-analysis, serum progesterone measurement can identify women at risk for ectopic pregnancy, but its discriminative capacity is insufficient to diagnose ectopic pregnancy with certainty19. Mathematical models based on the hCG ratio20, 21 have been developed to predict PUL outcome. These need to be tested prospectively in multicenter trials in order to evaluate their diagnostic performance in different populations. In most cases, uterine curettage should not play a role in the classification of PULs. It does not accurately differentiate between intra- and extrauterine pregnancies and may lead to inadvertent termination of a viable pregnancy22. A single-visit approach to the management of PULs is not appropriate, because it may result in an unacceptably large proportion of clinically significant ectopic pregnancies being missed23. The optimal clinical management of women with PULs involves reducing the number of visits without compromising the outcome of these pregnancies. In conclusion, consensus can be achieved in both the diagnostic approach and management of women with PULs. The panel agreed that because most PULs are at low risk of being an ectopic pregnancy, provided that the ultrasound examiner is sufficiently skilled and uses an ultrasound system with acceptable image quality, future efforts should concentrate on minimizing follow-up.