[1] Trondheim Reg & Univ Hosp, Natl Advisory Unit Pregnancy & Rheumat Dis, Dept Rheumatol, N-7006 Trondheim, Norway
[2] Trondheim Reg & Univ Hosp, Natl Ctr Fetal Med, Dept Obstet & Gynecol, N-7006 Trondheim, Norway
[3] Univ Bergen, Dept Global Publ Hlth & Primary Care, N-5020 Bergen, Norway
[4] Norwegian Inst Publ Hlth, Div Epidemiol, MBRN, Bergen, Norway