[1] Natl Univ Ireland Univ Coll Cork, Natl Perinatal Epidemiol Ctr, Cork, Ireland
[2] Natl Univ Ireland Univ Coll Cork, Dept Epidemiol & Publ Hlth, Cork, Ireland
[3] Natl Univ Ireland Univ Coll Cork, Anu Res Ctr, Cork, Ireland
[4] Aarhus Univ Hosp, Perinatal Epidemiol Res Unit, DK-8000 Aarhus, Denmark