[1] Aarhus Univ Hosp, Dept Obstet & Gynecol, Brendstrupgaardsvej 100, DK-8200 Aarhus N, Denmark
[2] Aarhus Univ, Dept Clin Med, Aarhus, Denmark
[3] Johns Hopkins Bloomberg Sch Publ Hlth, Baltimore, MD USA
[4] Univ New Mexico, Hlth Sci Ctr, Dept Internal Med, Albuquerque, NM 87131 USA
[5] Univ New Mexico, Hlth Sci Ctr, Dept Pathol, Albuquerque, NM 87131 USA