OC16.04: External validation of the M6 model and the two‐step triage system for pregnancies of unknown location. (30th September 2019) - Christodoulou, E.; Bobdiwala, S.; Kyriacou, C.; Farren, J.; Mitchell‐Jones, N.; Ayim, F.; Chohan, B.; Abhugazza, O.; Guruwadahyarhalli, B.; Al‐Memar, M.; Guha, S.; Vathanan, V.; et al.