[1] ST MARYS HOSP, SCH MED, DEPT OBSTET & GYNAECOL, LONDON W2 1PG, ENGLAND
[2] CENT MIDDLESEX HOSP, DEPT HAEMATOL, LONDON NW10, ENGLAND
[3] ST MARYS HOSP, SCH MED, DEPT HAEMATOL, LONDON W2 1PG, ENGLAND
[4] UCL HOSP, DEPT HAEMATOL, HAEMOSTASIS RES UNIT, LONDON WC1E 6HX, ENGLAND