[1] Boston Univ, Chobanian & Avedisian Sch Med, Boston, MA USA
[2] Boston Univ, Barry M Manuel Ctr Continuing Educ, Chobanian & Avedisian Sch Med, Boston, MA USA
[3] Boston Univ, Boston Med Ctr, Chobanian & Avedisian Sch Med, Dept Obstet & Gynecol, Boston, MA USA
[4] Boston Univ, Boston Med Ctr, Chobanian & Avedisian Sch Med, Dept Pediat, Boston, MA USA
[5] Boston Univ, Boston Med Ctr, Chobanian & Avedisian Sch Med, Dept Obstet & Gynecol, 85 E Concord St, Boston, MA 02118 USA