Rebecca Spencer1, Hilary Hewitt2, Laura McCarthy3, Ruwan Wimalasundera2, Pranav Pandya2. 1. Fetal Medicine Unit, Leeds General Infirmary and University of Leeds, UK r.n.spencer@leeds.ac.uk. 2. Fetal Medicine Unit, University College London Hospitals, UK. 3. Sunnybank Medical Centre, Wyke, Bradford.