Posted as supplied by author.

Collaborators: Glan Clwyd Hospital, Rhyl: Phillip Banfield, Christine Bell, Jeff Berry, Nigel Bickerton, Duncan Cameron, Lesley Furneaux, James Satelle, Matouk Zbaeda, and hospital midwives.

Alder Hey Children�s Hospital, Liverpool: David Pilling, consultant radiologist

Sheffield Children�s Hospital: Alan Sprigg, consultant radiologist

Bradford Royal Infirmary: Ian Beck, clinical lead in obstetrics and gynaecology; Carol Cahill, midwife; S Chatfield, consultant paediatrician; C Day, consultant paediatrician; Sian Jones, consultant obstetrician and gynaecologist; Derek Tuffnell, consultant obstetrician and gynaecologist; Jane West, clinical trials co-ordinator.

Ipswich Hospital: M Bamford, consultant paediatrician; SM Patient, consultant obstetrician and gynaecologist; DP Vasey, consultant obstetrician and gynaecologist.

Southmead Hospital, Bristol: Alera Awala, specialist registrar in obstetrics and gynaecology; Alison Leaf, consultant neonatogist; Thabani Sibanda, specialist registrar in obstetrics and gynaecology; Mr S K Vyas, consultant obstetrician and gynaecologist.

Hinchingbrooke Hospital, Huntingdon: H Blund, midwife; J Challener, consultant paediatrician; P Forbes, consultant obstetrician and gynaecologist; L Greaves, midwife; J Hare, consultant obstetrician; M Slack, consultant obstetrician and gynaecologist.

Royal Maternity Hospital, Belfast: Ms C Bailie, consultant in fetomaternal medicine; JC Dornan, professor of obstetrics and gynaecologist; C Holt, clinical midwifery manager; D McKenna, obstetric research fellow; R Tubman, consultant paediatrician.

Southport Hospital: Sharon Olorenshaw, midwife; Matouk Zbaeda, consultant paediatrician.

D. St George Hospital, Kogorah, Australia: Greg Davis, consultant obstetrician & gynaecologist.

Hope Hospital, Salford: Grant Mitchell, Consultant Obstetrician ; Mike Robinson, Consultant Paediatrician.

E. Grimsby Hospital: Mr Hopper, consultant obstetrician and gynaecologist.