[1] Univ London, St Georges Univ Hosp NHS Fdn Trust, Fetal Med Unit, London, England
[2] NHS Greater Glasgow & Clyde, Glasgow, Scotland
[3] Cristo Re Hosp, Dept Obstet & Gynecol, Rome, Italy
[4] St Georges Univ Hosp, Dept Neonatol, London, England
[5] Twins & Multiples Ctr Res & Clin Excellence, London, England
[6] Univ Liverpool, Liverpool Womens Hosp, Fetal Med Unit, Liverpool, England
[7] St Georges Univ London, Mol & Clin Sci Res Inst, Vasc Biol Res Ctr, London, England
[8] Univ London, St Georges Univ Hosp, Dept Obstet & Gynaecol, London SW17 0QT, England