1. Department of Obstetrics and Gynaecology; Institute for Clinical Medicine; Aarhus University Hospital; Aarhus University; Skejby Aarhus Denmark
2. Department of Gynaecology and Obstetrics; Nordsjaellands Hospital; University of Copenhagen; Hillerød Denmark
3. Department of Gynaecology and Obstetrics; Hvidovre Hospital; University of Copenhagen; Hvidovre Denmark
4. Department of Obstetrics; Copenhagen University Hospital; Rigshospitalet; Copenhagen Denmark
5. Department of Gynaecology and Obstetrics; University Hospital of Odense; Odense Denmark
6. Department of Gynaecology and Obstetrics; Aalborg University Hospital; Aalborg Denmark
7. Department of Paediatrics; Aarhus University Hospital; Skejby Denmark
8. Copenhagen Prospective Studies on Asthma in Childhood; Herlev Denmark
9. Gentofte Hospital; University of Copenhagen; Copenhagen Denmark