Presentation Details
| Platelet indices in healthy pregnancies Laura M.Dionisio, Giovani M.Favero. State University of Ponta Grossa, Ponta Grossa, Brazil |
Abstract
Background: Platelet abnormalities can affect its hemostatic and non-hemostatic roles, and lead to complications during pregnancy and postpartum. Platelet indices are easily measured by hematology analyzers from a wide number of manufacturers. These indices have been studied in numerous pregnancy-related conditions like premature delivery, gestational diabetes, preeclampsia, ectopic pregnancy, and intrauterine growth restriction Considering the physiological changes in platelets during healthy and pathologic pregnancies, and the potential clinical use of these parameters, it is needed to fully comprehend how these changes affect the platelet indices in pregnant patients. Objectives: This study aimed to establish reference values for platelet indices in healthy pregnant and non-pregnant Brazilian women and to evaluate the differences between the trimesters and between pregnant and non-pregnant women. Methods: 2mL of venous blood samples were collected into EDTA-K-2 tubes and tested for whole blood count using the Sysmex XN1000 hematology analyzer. All healthy pregnant women with no adverse medical or obstetric history were recruited. The non-pregnant women were healthy adult volunteers. The parameters included were: impedance platelet count (PLT-I), fluorescence platelet count (PLT-F), mean platelet volume (MPV), platelet distribution width (PDW), plateletcrit (PCT), platelet large cell ratio (P-LCR) and immature platelet fraction (IPF%). All statistical calculations were performed with R (3.6.1). As the data showed a non-normal distribution, reference intervals were calculated using a nonparametric method for lower and upper reference limits as 2.5% and 97.5% of the reference distribution. The significance of between-group differences was tested by Mann-Whitney and Kruskal-Wallis tests. Statistical significance was set to P <0.05. Results: 240 women (120 non-pregnant and 120 pregnant) were enrolled in this study. For the pregnant group, there were 25 patients in the first trimester, 49 in the second, and 46 in the third. We obtained reference intervals for the platelet indices for pregnant and non-pregnant women. (Figure 1). The platelet count (PLT-I and PLT-F) and PCT were lower (p<0.001) for the pregnant women. Between-trimesters comparison showed significant differences only for PLT-I (p= 0.0134) and PLT-F (p=0.0271). Discussion: Both healthy and pathologic pregnancies are characterized by marked modifications of physiological functions, including hemostasis and therefore platelets. The reduced platelet counts in pregnant women are some of the most frequent alterations in hemostasis during normal pregnancies, mainly in the third trimester. These modifications in hemostasis are consequences of physiological hormonal changes as a part of an adaptation process. Also, the lower platelet counts in pregnancy are attributed to increased platelet turnover and hemodilution. Our study reported a gradual reduction in platelet count from the first to the third trimester, which was described previously. Although normal pregnancy is associated with increased platelet turnover, the parameters associated with platelet activation and production MPV, PDW, P-LCR, IPF % were not increased in the pregnant group. Indeed, platelet activation in normal pregnancies remains controversial, possibly due to the diversity of biomarkers to assess platelet activation. Conclusion: Considering the differences between pregnant and non-pregnant and the physiological changes in hemostasis during pregnancy, pregnancy-specific reference ranges for platelet parameters are essential for adequate clinical interpretation.
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No part of this publication may be reproduced, distributed, or transmitted in any form or by any means, including photocopying, recording, or other electronic or mechanical methods, without the prior written permission of the author.