[1] Norwegian Univ Sci & Technol, Dept Circulat & Med Imaging, N-7491 Trondheim, Norway
[2] St Olavs Hosp, Womens Clin, Trondheim, Norway
[3] NTNU Norwegian Univ Sci & Technol, Fac Med & Hlth Sci, Dept Publ Hlth & Nursing, Trondheim, Norway
[4] Queen Maud Univ, Coll Early Childhood Educ, Dept Phys Act & Hlth, Trondheim, Norway
[5] St Olavs Hosp, Clin Anaesthesia & Intens Care, Trondheim, Norway