Anne Britt Vika Nilsen*, Ulla Waldenström, Svein Rasmussen, Anna Hjelmstedt and Erica Schytt
* Corresponding author: Anne Britt Vika Nilsen abvn@hib.no
BMC Pregnancy and Childbirth 2013, 13:29 doi:10.1186/1471-2393-13-29