Ultrasound characteristics, serum biochemistry and outcomes for ectopic pregnancies presenting during the SARS-CoV-2 pandemic: retrospective analysis - Kyriacou, C; Cooper, N; Robinson, E; Parker, N; Barcroft, J; Kundu, S; Letchworth, P; Sur, S; Gould, D; Stalder, C; Bourne, T (Ultrasound in Obstetrics and Gynecology, 2021)