[1] Cedars Sinai Med Ctr, Burns Allen Res Inst, Dept Obstet & Gynecol, Los Angeles, CA 90048 USA
[2] Univ Calif Los Angeles, Dept Obstet & Gynecol, David Geffen Sch Med, Los Angeles, CA 90095 USA
[3] Univ Calif Los Angeles, Div Gen Internal Med & Hlth Serv Res, David Geffen Sch Med, Los Angeles, CA 90095 USA
[4] UCLA, Fielding Sch Publ Hlth, Dept Community Hlth Sci, Los Angeles, CA USA
[5] UCLA, Fielding Sch Publ Hlth, Dept Hlth Policy & Management, Los Angeles, CA USA
[6] Childbirth Res Associates, North Hollywood, CA USA
[7] BirthSwell, Ithaca, NY USA
[8] AMF Consulting, Los Angeles, CA USA