Affiliation: | 1. Fetal Medicine Unit, University College Hospital, Department of Obstetrics and Gynaecology, University College and Middlesex School of Medicine, 86–96 Chenies Mews, London WC1E and Institute of Child Health, 30 Guilford Street, London WC1, U.K.;2. Department of Histopathology, St Bartholomew's Hospital Medical College, West Smithfield, London EC1A 7 BE, U.K. |