1. Perinatology Research Branch, Eunice Kennedy Shriver National Institute of Child Health and Human Development/National Institutes of Health/Department of Health and Human Services; Bethesda MD, and Detroit, MI USA
2. Nuffield Department of Obstetrics & Gynaecology; University of Oxford, Women's Centre, John Radcliffe Hospital; Oxford UK
3. Oxford Maternal & Perinatal Health Institute; Green Templeton College; Oxford UK