[1] Univ Dundee, Ninewells Hosp & Med Sch, Dept Transfus Med, Dundee DD1 9SY, Scotland
[2] Royal Infirm, Dept Haematol, Glasgow G31 2ER, Lanark, Scotland
[3] Univ Glasgow, Royal Infirm, Dept Obstet & Gynaecol, Glasgow, Lanark, Scotland
[4] Stobhill Gen Hosp, Dept Res & Dev, Glasgow G21 3UW, Lanark, Scotland