1600 John F. Kennedy Boulevard • Suite 1800 • Philadelphia, Pennsylvania, 19103-2899
OBSTETRICS AND GYNECOLOGY CLINICS OF NORTH AMERICA Volume 42, Number 4
December 2015 ISSN 0889-8545, ISBN-13: 978-0-323-40258-3
Editor: Kerry Holland
Developmental Editor: Kristen Helm
© 2015 Elsevier Inc. All rights reserved.
This periodical and the individual contributions contained in it are protected under copyright by Elsevier, and the following terms and conditions apply to their use:
Single photocopies of single articles may be made for personal use as allowed by national copyright laws. Permission of the Publisher and payment of a fee is required for all other photocopying, including multiple or systematic copying, copying for advertising or promotional purposes, resale, and all forms of document delivery. Special rates are available for educational institutions that wish to make photocopies for non-profit educational classroom use. For information on how to seek permission visit www.elsevier.com/permissions or call: (+44) 1865 843830 (UK)/(+1) 215 239 3804 (USA).
Subscribers may reproduce tables of contents or prepare lists of articles including abstracts for internal circulation within their institutions. Permission of the Publisher is required for resale or distribution outside the institution. Permission of the Publisher is required for all other derivative works, including compilations and translations (please consult www.elsevier.com/permissions).
Electronic Storage or Usage
Permission of the Publisher is required to store or use electronically any material contained in this periodical, including any article or part of an article (please consult www.elsevier.com/permissions). Except as outlined above, no part of this publication may be reproduced, stored in a retrieval system or transmitted in any form or by any means, electronic, mechanical, photocopying, recording or otherwise, without prior written permission of the Publisher.
No responsibility is assumed by the Publisher for any injury and/or damage to persons or property as a matter of products liability, negligence or otherwise, or from any use or operation of any methods, products, instructions or ideas contained in the material herein. Because of rapid advances in the medical sciences, in particular, independent verification of diagnoses and drug dosages should be made.
Although all advertising material is expected to conform to ethical (medical) standards, inclusion in this publication does not constitute a guarantee or endorsement of the quality or value of such product or of the claims made of it by its manufacturer.
Obstetrics and Gynecology Clinics (ISSN 0889-8545) is published quarterly by Elsevier Inc., 360 Park Avenue South, New York, NY 10010-1710. Months of issue are March, June, September, and December. Periodicals postage paid at New York, NY, and additional mailing offices. Subscription price per year is $310.00 (US individuals), $545.00 (US institutions), $155.00 (US students), $370.00 (Canadian individuals), $688.00 (Canadian institutions), $225.00 (Canadian students), $450.00 (international individuals), $688.00 (international institutions), and $225.00 (international students). To receive student/resident rate, orders must be accompanied by name of affiliated institution, date of term, and the signature of program/residency coordinator on institution letterhead. Orders will be billed at individual rate until proof of status is received. Foreign air speed delivery is included in all Clinics subscription prices. All prices are subject to change without notice. POSTMASTER: Send address changes to Obstetrics and Gynecology Clinics, Elsevier Health Sciences Division, Subscription Customer Service, 3251 Riverport Lane, Maryland Heights, MO 63043. Customer Service: Telephone: 1-800-654-2452 (U.S. and Canada); 314-447-8871 (outside U.S. and Canada). Fax: 314-447-8029. E-mail: (for print support); (for online support).
Reprints. For copies of 100 or more of articles in this publication, please contact the Commercial Reprints Department, Elsevier Inc., 360 Park Avenue South, New York, New York 10010-1710. Tel.: 212-633-3874; Fax: 212-633-3820; E-mail: email@example.com.
Obstetrics and Gynecology Clinics of North America is also published in Spanish by McGraw-Hill Interamericana Editores S.A., P.O. Box 5-237, 06500, Mexico; in Portuguese by Reichmann and Affonso Editores, Rio de Janeiro, Brazil; and in Greek by Paschalidis Medical Publications, Athens, Greece.
Obstetrics and Gynecology Clinics of North America is covered in MEDLINE/PubMed (Index Medicus), Excerpta Medica, Current Concepts/Clinical Medicine, Science Citation Index, BIOSIS, CINAHL, and ISI/BIOMED.
Printed in the United States of America.