[1] Univ Hosp Birmingham NHS Fdn Trust, Ctr Clin Haematol, Birmingham, England
[2] Golden Jubilee Natl Hosp, Dept Cardiol, West Scotland Reg Heart & Lung Ctr, Clydebank, Scotland
[3] Manchester Univ NHS Fdn Trust, Dept Anaesthet, Manchester, England
[4] Leeds Teaching Hosp NHS Trust, Dept Obstet & Gynaecol, Leeds, England
[5] Guys & St Thomas NHS Fdn Trust, Womens Serv, London, England
[6] Univ Hosp Bristol NHS Fdn Trust, Dept Obstet, Bristol, England
[7] NHS Lothian, Dept Haematol, Edinburgh, Scotland
[8] Newcastle Tyne Hosp NHS Fdn Trust, Dept Matern, Newcastle Upon Tyne, England
[9] Univ Bristol, Cellular & Mol Med, Bristol, England
[10] Bristol Haematol & Oncol Ctr, Bristol, England
[11] Birmingham Womens & Childrens NHS Fdn Trust, Dept Matern, Birmingham, England
[12] Manchester Univ NHS Fdn Trust, Dept Obstet & Maternal & Fetal Med, Manchester, England
[13] Univ Hosp Birmingham NHS Fdn Trust, Ctr Clin Haematol, Birmingham B152TH, England