1. National Perinatal Epidemiology Centre; Department of Obstetrics and Gynaecology; Cork University Maternity Hospital; Wilton; Cork; Ireland
2. Anu Research Centre; Department of Obstetrics and Gynaecology; Cork University Maternity Hospital; Wilton; Cork; Ireland
3. Perinatal Epidemiology Research Unit; Department of Paediatrics; Aarhus University Hospital; Aarhus; Denmark
4. Department of Epidemiology and Public Health; University College Cork; Cork; Ireland