[1] Norwegian Univ Sci & Technol NTNU, Fac Med & Hlth Sci, Trondheim, Norway
[2] Trondheim Reg & Univ Hosp, St Olavs Hosp, Clin Clin Serv, Trondheim, Norway
[3] Norwegian Univ Sci & Technol NTNU, Dept Publ Hlth & Nursing, Trondheim, Norway
[4] Trondheim Reg & Univ Hosp, St Olavs Hosp, Dept Obstet & Gynecol, Trondheim, Norway
[5] Norwegian Univ Sci & Technol NTNU, Dept Clin & Mol Med, Trondheim, Norway
[6] Trondheim Reg & Univ Hosp, St Olavs Hosp, Childrens Clin, Trondheim, Norway
[7] Norwegian Univ Sci & Technol NTNU, Dept Clin & Mol Med, POB 8905, NO-7491 Trondheim, Norway