[1] Norwegian Univ Sci & Technol, Natl Serv Pregnancy & Rheumat Dis, Dept Rheumatol, Univ Trondheim Hosp,Dept Neurosci, N-7034 Trondheim, Norway
[2] Diakonhjemmet Hosp, Dept Rheumatol, Oslo, Norway
[3] Univ Trondheim Hosp, Natl Serv Pregnancy & Rheumat Dis, Dept Rheumatol, Trondheim, Norway
[4] Lund Univ, Dept Obstet & Gynecol, Clin Sci, Lund, Sweden
[5] Norwegian Univ Sci & Technol, Dept Lab Med, Womens & Child Hlth, N-7034 Trondheim, Norway
[6] Univ Bergen, Dept Global Publ Hlth & Primary Care, Med Birth Registry Norway, Norwegian Inst Publ Hlth,Div Epidemiol, Bergen, Norway