Thrombocytopenia in pregnant women is diagnosed frequently by obstetricians because platelet counts are included with automated complete blood cell counts (CBCs) obtained during routine prenatal screening (1). Although most U.S. health care providers are trained using U.S. Conventional Units, most scientists, journals, and countries use Système International (SI) units. The laboratory results reported in U.S. Conventional Units can be converted to SI Units or vice versa by using a conversion factor. The conversion factor for platelet count results is 1.0 (ie, to convert from x 103/μL, multiply by 1.0, to get x 109/L). Thrombocytopenia, defined as a platelet count of less than 150 x 109/L, is common and occurs in 7–12% of pregnancies (2, 3). Thrombocytopenia can result from a variety of physiologic or pathologic conditions, several of which are unique to pregnancy. Some causes of thrombocytopenia are serious medical disorders that have the potential for maternal and fetal morbidity. In contrast, other conditions, such as gestational thrombocytopenia, are benign and pose no maternal or fetal risks. Because of the increased recognition of maternal and fetal thrombocytopenia, there are numerous controversies about obstetric management of this condition. Clinicians must weigh the risks of maternal and fetal bleeding complications against the costs and morbidity of diagnostic tests and invasive interventions.
For a comprehensive overview of thrombocytopenia in pregnancy, the fulltext version of this Practice Bulletin is available at http://dx.doi.org/10.1097/AOG.0000000000001641 .
Committee on Practice Bulletins—Obstetrics. This Practice Bulletin was developed by the American College of Obstetricians and Gynecologists’ Committee on Practice Bulletins—Obstetrics in collaboration with Mark Turrentine, MD.
The information is designed to aid practitioners in making decisions about appropriate obstetric and gynecologic care. These guidelines should not be construed as dictating an exclusive course of treatment or procedure. Variations in practice may be warranted based on the needs of the individual patient, resources, and limitations unique to the institution or type of practice.
Copyright September 2016 by the American College of Obstetricians and Gynecologists. All rights reserved. No part of this publication may be reproduced, stored in a retrieval system, posted on the Internet, or transmitted, in any form or by any means, electronic, mechanical, photocopying, recording, or otherwise, without prior written permission from the publisher.
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Official Citation: Thrombocytopenia in pregnancy. Practice Bulletin No. 166. American College of Obstetricians and Gynecologists. Obstet Gynecol 2016; 128:e43–53.
Received July 19, 2016
Accepted July 19, 2016