Serial prophylactic exchange blood transfusion in pregnant women with sickle cell disease (TAPS-2): study protocol for a randomised controlled feasibility trial oleh Laura L. Oakley, Moji Awogbade, Sarah Brien, Annette Briley, Maria Chorozoglou, Emma Drasar, Jemma Johns, Elizabeth Rhodes, Vicky Robinson, Paul Seed, Joseph Sharif, Claire Singh, Paul Telfer, Hilary Thompson, Ingrid Watt-Coote, Jo Howard, Eugene Oteng-Ntim