Preoperative moderate thrombocytopenia is not associated with increased blood loss for low-risk cesarean section: a retrospective cohort study

Immune thrombocytopenia and pregnancy: challenges and opportunities in diagnosis and management

INTRODUCTION

Immune thrombocytopenia (ITP) affecting pregnancy is a diagnostic and often a therapeutic challenge.

AREAS COVERED

We review the current diagnostic criteria for ITP in pregnancy and the potential utility of laboratory tests. We discuss the impact of ITP on pregnancy outcomes and the effects of pregnancy on patients living with chronic ITP.  We describe the criteria for intervention, the evidence supporting first-line treatment approaches and the therapeutic decisions and challenges in cases refractory to steroids and IVIG. We review the evidence supporting the potential use of thrombopoietin receptor agonists for refractory thrombocytopenia. Finally, we describe the diagnostic, prognostic, and treatment approaches to neonatal ITP and considerations regarding breastfeeding. We searched the terms 'immune thrombocytopenia' and 'pregnancy' on PubMed to identify the relevant literature published before 31 December 2023, including within cited references.

EXPERT OPINION

Decreased platelet production may play a role in pregnancy-related ITP exacerbation. Putative mechanisms include placental hormones, such as inhibin. Although IVIG and prednisone usually suffice to achieve hemostasis for delivery, second-line agents are sometimes required to allow for neuraxial anesthesia. There is growing evidence supporting the use of romiplostim during pregnancy; however, its risk of venous thromboembolism warrants further evaluation.

Hemostatic biomarkers associated with postpartum hemorrhage: a systematic review and meta-analysis

Postpartum hemorrhage (PPH) is a leading cause of maternal morbi-mortality. Although obstetric risk factors are well described, the impact of predelivery hematologic and hemostatic biomarkers remains incompletely understood. In this systematic review, we aimed to summarize the available literature on the association between predelivery hemostatic biomarkers and PPH/severe PPH. Searching MEDLINE, EMBASE, and CENTRAL databases from inception to October 2022, we included observational studies on unselected pregnant women without bleeding disorder reporting on PPH and on predelivery hemostatic biomarkers. Two review authors independently performed title, abstract and full-text screening, upon which quantitative syntheses of studies reporting on the same hemostatic biomarker were conducted, calculating the mean difference (MD) between women with PPH/severe PPH and controls. A search on 18 October 2022 yielded 81 articles fitting our inclusion criteria. The heterogeneity between studies was considerable. With regard to PPH, the estimated average MD in the investigated biomarkers (platelets, fibrinogen, hemoglobin, Ddimer, activated partial thromboplastin time, and prothrombin time) were not statistically significant. Women who developed severe PPH had lower predelivery platelets than controls (MD = -26.0 109/L; 95% confidence interval, -35.8 to -16.1), whereas differences in predelivery fibrinogen concentration (MD = -0.31 g/L; 95% confidence interval, -0.75 to 0.13) and levels of factor XIII or hemoglobin were not statistically significant in women with and without severe PPH. Predelivery platelet counts were, on average, lower in women with severe PPH compared with controls, suggesting the potential usefulness of this biomarker for predicting severe PPH. This trial was registered at the International Prospective Register of Systematic Reviews as CRD42022368075.

Prediction and Evaluation of Machine Learning Algorithm for Prediction of Blood Transfusion during Cesarean Section and Analysis of Risk Factors of Hypothermia during Anesthesia Recovery

Objective

To explore the application of machine learning algorithm in the prediction and evaluation of cesarean section, predicting the amount of blood transfusion during cesarean section and to analyze the risk factors of hypothermia during anesthesia recovery.

Methods

(1)Through the hospital electronic medical record of medical system, a total of 600 parturients who underwent cesarean section in our hospital from June 2019 to December 2020 were included. The maternal age, admission time, diagnosis, and other case data were recorded. The routine method of cesarean section was intraspinal anesthesia, and general anesthesia was only used for patients' strong demand, taboo, or failure of intraspinal anesthesia. According to the standard of intraoperative bleeding, the patients were divided into two groups: the obvious bleeding group (MH group, N = 154) and nonobvious hemorrhage group (NMH group, N = 446). The preoperative, intraoperative, and postoperative indexes of parturients in the two groups were analyzed and compared. Then, the risk factors of intraoperative bleeding were screened by logistic regression analysis with the occurrence of obvious bleeding as the dependent variable and the factors in the univariate analysis as independent variables. In order to further predict intraoperative blood transfusion, the standard cases of recesarean section and variables with possible clinical significance were included in the prediction model. Logistic regression, XGB, and ANN3 machine learning algorithms were used to construct the prediction model of intraoperative blood transfusion. The area under ROC curve (AUROC), accuracy, recall rate, and F1 value were calculated and compared. (2) According to whether hypothermia occurred in the anesthesia recovery room, the patients were divided into two groups: the hypothermia group (N = 244) and nonhypothermia group (N = 356). The incidence of hypothermia was calculated, and the relevant clinical data were collected. On the basis of consulting the literatures, the factors probably related to hypothermia were collected and analyzed by univariate statistical analysis, and the statistically significant factors were analyzed by multifactor logistic regression analysis to screen the independent risk factors of hypothermia in anesthetic convalescent patients.

Results

(1) First of all, we compared the basic data of the blood transfusion group and the nontransfusion group. The gestational age of the transfusion group was lower than that of the nontransfusion group, and the times of cesarean section and pregnancy in the transfusion group were higher than those of the non-transfusion group. Secondly, we compared the incidence of complications between the blood transfusion group and the nontransfusion group. The incidence of pregnancy complications was not significantly different between the two groups (P > 0.05). The incidence of premature rupture of membranes in the nontransfusion group was higher than that in the transfusion group (P < 0.05). There was no significant difference in the fetal umbilical cord around neck, amniotic fluid index, and fetal heart rate before operation in the blood transfusion group, but the thickness of uterine anterior wall and the levels of Hb, PT, FIB, and TT in the blood transfusion group were lower than those in the nontransfusion group, while the number of placenta previa and the levels of PLT and APTT in the blood transfusion group were higher than those in the nontransfusion group. The XGB prediction model finally got the 8 most important features, in the order of importance from high to low: preoperative Hb, operation time, anterior wall thickness of the lower segment of uterus, uterine weakness, preoperative fetal heart, placenta previa, ASA grade, and uterine contractile drugs. The higher the score, the greater the impact on the model. There was a linear correlation between the 8 features (including the correlation with the target blood transfusion). The indexes with strong correlation with blood transfusion included the placenta previa, ASA grade, operation time, uterine atony, and preoperative Hb. Placenta previa, ASA grade, operation time, and uterine atony were positively correlated with blood transfusion, while preoperative Hb was negatively correlated with blood transfusion. In order to further compare the prediction ability of the three machine learning methods, all the samples are randomly divided into two parts: the first 75% training set and the last 25% test set. Then, the three models are trained again on the training set, and at this time, the model does not come into contact with the samples in any test set. After the model training, the trained model was used to predict the test set, and the real blood transfusion status was compared with the predicted value, and the F1, accuracy, recall rate, and AUROC4 indicators were checked. In terms of training samples and test samples, the AUROC of XGB was higher than that of logistic regression, and the F1, accuracy, and recall rate of XGB of ANN were also slightly higher than those of logistic regression and ANN. Therefore, the performance of XGB algorithm is slightly better than that of logistic regression and ANN. (2) According to the univariate analysis of hypothermia during the recovery period of anesthesia, there were significant differences in ASA grade, mode of anesthesia, infusion volume, blood transfusion, and operation duration between the normal body temperature group and hypothermia group (P < 0.05). Logistic regression analysis showed that ASA grade, anesthesia mode, infusion volume, blood transfusion, and operation duration were all risk factors of hypothermia during anesthesia recovery.

Conclusion

In this study, three machine learning algorithms were used to analyze the large sample of clinical data and predict the results. It was found that five important predictive variables of blood transfusion during recesarean section were preoperative Hb, expected operation time, uterine weakness, placenta previa, and ASA grade. By comparing the three algorithms, the prediction effect of XGB may be more accurate than that of logistic regression and ANN. The model can provide accurate individual prediction for patients and has good prediction performance and has a good prospect of clinical application. Secondly, through the analysis of the risk factors of hypothermia during the recovery period of cesarean section, it is found that ASA grade, mode of anesthesia, amount of infusion, blood transfusion, and operation time are all risk factors of hypothermia during the recovery period of cesarean section. In line with this, the observation of this kind of patients should be strengthened during cesarean section.

Mild thrombocytopenia and the risk for postpartum hemorrhage in twin pregnancies

OBJECTIVE

We aimed to investigate the association of mild thrombocytopenia with postpartum hemorrhage (PPH) and blood transfusion among women with twin gestations.

METHODS

A retrospective cohort study (Jan 2015 to May 2019) was performed. Women with twin pregnancies and pre-delivery mild thrombocytopenia were compared to those with normal platelet count. The primary outcome was the rate of PPH, defined as a composite of one or more of the following: (1) need for packed red blood cell transfusion; (2) postpartum hemoglobin decline of ≥3 g/dL; and (3) the use of postpartum uterotonics agents in addition to oxytocin.

RESULTS

Of 1085 women who were included in final analysis, 315 (30.9%) had mild thrombocytopenia (and 770 (69.1%) served as controls. The rate of PPH was increased in the study group (14% vs. 9.4%, P = 0.03), as was the use of uterotonic agents (3.8% vs. 1.3%, respectively, P = 0.02). The rate of blood product transfusion and hemoglobin decline >3 g/dL was not significantly different between the groups. In multivariate logistic regression analysis, mild thrombocytopenia was associated with a higher risk for PPH (OR 1.55 [95% CI 1.02-2.35], P = 0.02).

CONCLUSION

Mild thrombocytopenia in twin pregnancies is associated with an increased risk of interventions such as the use of uterotonic agents.

Gestational Thrombocytopenia: A Review on Recent Updates

Thrombocytopenia is a condition in which the blood platelet count is low. It is well established that the mild thrombocytopenia frequency is higher in normal pregnancy. This type of thrombocytopenia was named pregnancy-induced thrombocytopenia. However, recently, it has been widely known as gestational thrombocytopenia (GT). The rate is higher in women with a prior GT history and multiple pregnancies. However, it appears that GT is a physiological response to the pregnancy; placenta's peculiar structure and its unique blood flow pattern play major roles in GT development. There are no specific, precise, or known underlying pathophysiological mechanisms of GT, and no new specific management strategies are published yet. Therefore, we decided to do a non-systematic review of any recent updates that had been published in PubMed, EMBASE, and Web of Science about the pathophysiology of GT, its treatment, and other related topics.

Platelet count and indices as postpartum hemorrhage risk factors: a retrospective cohort study

BACKGROUND

Severe postpartum hemorrhage (SPPH) is the leading cause of maternal mortality and morbidity worldwide. Platelet anomalies frequently occur during pregnancy. However, their role in the etiology of SPPH is largely unknown.

OBJECTIVE

To study the relation between platelet parameters and SPPH.

METHODS

This retrospective single-center cohort included deliveries between 2009 and 2017. SPPH was defined as ≥1000 ml blood loss within 24 h after delivery. Platelet parameters were measured within 72 h before delivery. Multiple imputation was performed for missing data. Odds ratios were adjusted (aORs) for maternal age, multiple gestation, macrosomia, induction of labor, preeclampsia, and hemolysis, elevated liver enzymes, and low platelets syndrome.

RESULTS

A total of 23 205 deliveries were included. Of the 2402 (10.4%) women with thrombocytopenia (<150 × 109 /L), 10.3% developed SPPH, compared with 7.6% of women with a normal platelet count (aOR: 1.34, 95% CI: 1.14-1.59). Women with a platelet count of <50 × 109 /L were most at risk (aOR of 2.24 [1.01-4.94]) compared with the reference group with normal platelet counts; the aOR was 1.22 (0.77-1.93) for the 50-99 × 109 /L platelet count group and 1.31 (1.10-1.56) for the 100-149 × 109 /L platelet count group. Plateletcrit was associated with SPPH (aOR 1.15 [1.08-1.21] per 0.05% decrease), and, although rarely present, a platelet distribution width (PDW) ≥23% (n = 22) also increased the odds of SPPH (aOR 6.05 [2.29-16.20]).

CONCLUSION

Different degrees of thrombocytopenia were independently associated with the occurrence of SPPH. Despite their relation to SPPH, plateletcrit and a PDW of ≥23% have limited additional value in addition to platelet count.

Gestational thrombocytopenia: a case-control study of over 3,500 pregnancies

Gestational thrombocytopenia (GT) affects an estimated nine million women annually. Women with GT have recurrent episodes on subsequent pregnancies suggesting that GT is related to a maternal factor rather than a factor unique to the individual pregnancy. We performed a case-control study of over 3 500 pregnancies at a single hospital during 2017. We defined GT as any pregnancy with a platelet count <150 000/µl during the 100 days prior to delivery. We excluded women with platelet counts <50 000/µl or with conditions known to cause thrombocytopenia. GT was present in 12% of pregnancies. The median platelet count at delivery was 134 500/µl in cases versus 208 000/µl in controls, P < 0·0001. During the pregnancy, the platelet count declined 31·8% in cases compared with 18·3% in controls (P < 0·0001) in association with a significant increase in mean platelet volume during each trimester. Among women with GT, platelet counts rapidly increased during the first week postpartum, consistent with a mechanism directly related to high blood flow rates in the gravid uterus. GT, a recurrent condition of at-risk women, is a common haematological disorder of pregnancy. Future research may focus on genetic gain-of-function polymorphisms resulting in increased turnover of platelets uncovered only during periods of high-shear blood flow.

Mild thrombocytopenia prior to elective cesarean section is an independent risk factor for blood transfusion

PURPOSE

Thrombocytopenia is the second most common hematological disorder in pregnancy and complicates approximately 10% of all pregnancies. The data regarding the association of mild thrombocytopenia in women undergoing cesarean section and risk of bleeding or bleeding-related complications are scarce. Thus, the aim of the current study was to assess the association of mild thrombocytopenia with hemorrhage-related morbidities, among patients undergoing elective cesarean section.

METHODS

We performed a retrospective cohort study, in a single tertiary university-affiliated medical center, between 1 January 2012 and 31 May 2019. Medical charts of women who underwent elective cesarean section at term (37^+0/7-41 + ^6/7 weeks of gestations) were retrieved and analyzed. We compared women with mild thrombocytopenia (platelet count of 100-149 × 10³/μL) to women with normal platelet count (150-450 × 10³/μL). The primary outcome was the need for red blood cell transfusion during the index admission. A secondary outcome was severe bleeding not requiring blood transfusion defined as postpartum hemoglobin decline of  ≥ 3 g/dL as compared to the prepartum levels.

RESULTS

During the study period, 1577 women were included in the final analysis, of them 396 (25.11%) had mild thrombocytopenia prior to delivery. As compared to the control group, women with mild thrombocytopenia had higher rates of blood transfusion (3.79 vs. 1.52%, p = 0.01), and had a significant decline in hemoglobin levels. In a multivariable logistic regression model, mild thrombocytopenia was independently associated with blood transfusion with adjusted OR of 2.34 (95% CI 1.10-4.96, p = 0.03).

CONCLUSION

Preoperative mild thrombocytopenia is associated with an increased risk of blood loss and blood transfusion in women undergoing elective CS. More studies are required to assess those observations in context of urgent cesarean sections and whether any preventive measures can reduce the risk for bleeding.