[1] UNIV LONDON KINGS COLL HOSP, SCH MED & DENT, DEPT OBSTET & GYNAECOL, OBSTET ULTRASOUND UNIT, LONDON SE5 8RX, ENGLAND
[2] UNIV ZAGREB, INST ULTRASON, DEPT OBSTET & GYNAECOL, YU-41001 ZAGREB, CROATIA
[3] HISTOPATHOL INST LOVERAL, DEPT OBSTET & GYNAECOL, LOVERAL, BELGIUM