. Author manuscript; available in PMC: 2013 Feb 1.
Published in final edited form as: Obstet Gynecol. 2012 Feb;119(2 Pt 2):480–483. doi: 10.1097/AOG.0b013e3182390622
© 2012 by The American College of Obstetricians and Gynecologists. Published by Lippincott Williams & Wilkins.