[1] Virginia Commonwealth Univ, Med Coll Virginia, Dept Med, Richmond, VA 23298 USA
[2] Hosp Clin Caracas, Caracas 1040, Venezuela
[3] Cent Univ Venezuela, Caracas 1040, Venezuela
[4] Virginia Commonwealth Univ, Med Coll Virginia, Dept Obstet & Gynecol, Richmond, VA 23298 USA
[5] Univ Cent Hosp, Biomedicum, Dept Clin Chem, SF-00290 Helsinki, Finland
[6] Univ Helsinki, Cent Hosp, Biomedicum, Dept Obstet & Gynecol, SF-00290 Helsinki, Finland
[7] Univ Sherbrooke, Dept Med, Sherbrooke, PQ J1H 5N4, Canada