. Author manuscript; available in PMC: 2014 Nov 6.
Published in final edited form as: Obstet Gynecol. 2006 Dec;108(6):1439–1447. doi: 10.1097/01.AOG.0000243775.73788.11
© 2006 by The American College of Obstetricians and Gynecologists. Published by Lippincott Williams & Wilkins.