[1] Harvard Med Sch, Boston, MA 02115 USA
[2] Massachusetts Gen Hosp, Dept Obstet & Gynecol, Boston, MA 02114 USA
[3] Massachusetts Gen Hosp, Div Infect Dis, Boston, MA USA
[4] Brigham & Womens Hosp, Dept Obstet & Gynecol, 75 Francis St, Boston, MA 02115 USA
[5] Brigham & Womens Hosp, Div Infect Dis, 75 Francis St, Boston, MA 02115 USA
[6] Newton Wellesley Hosp, Dept Obstet Gynecol, Newton, MA USA
[7] Brigham & Womens Hosp, Dept Nursing, 75 Francis St, Boston, MA 02115 USA
[8] Dept Pediat Newborn Med, Boston, MA USA
[9] Massachusetts Gen Hosp, Infect Control Unit, Boston, MA 02114 USA