[1] Kaiser Permanente West Los Angeles Med Ctr, Dept Maternal Fetal Med, Los Angeles, CA USA
[2] Southern Calif Permanente Med Grp, Pasadena, CA USA
[3] Kaiser Permanente Baldwin Pk Med Ctr, Dept Obstet & Gynecol, Baldwin Pk, CA USA
[4] Kaiser Permanente Anaheim Med Ctr, Dept Neonatal Med, Anaheim, CA USA
[5] Kaiser Permanente South Bay Med Ctr, Dept Neonatal Med, Los Angeles, CA USA
[6] Kaiser Fdn Hosp, Pasadena, CA USA
[7] Southern Calif Permanente Med Grp Reg Reference L, North Hollywood, CA USA
[8] Kaiser Permanente Southern Calif, Dept Res & Evaluat, Pasadena, CA USA
[9] Kaiser Permanente Irvine Med Ctr, Dept Maternal Fetal Med, Irvine, CA USA
[10] Kaiser Permanente San Diego Med Ctr, Dept Maternal Fetal Med, San Diego, CA USA
[11] Kaiser Permanente Bernard J Tyson Sch Med, Dept Hlth Syst Sci, Pasadena, CA USA