Incidence of postpartum hemorrhage based on the improved combined method in evaluating blood loss: A retrospective cohort study

PLOS ONE RESEARCH ARTICLE Incidence of postpartum hemorrhage based on the improved combined method in evaluating blood loss: A retrospective cohort study Fangyuan Zheng ID1, Haiyan Wen ID1*, Lan Shi2, Caihe Wen1, Qiumeng Wang1, Shouzhen Yao1 1 Department of Obstetrics, Hangzhou Women’s Hospital, Hangzhou, China, 2 Department of Fourth Clinical Medical College, Zhejiang Chinese Medical University, Hangzhou, China a1111111111 a1111111111 a1111111111 a1111111111 a1111111111 * Abstract Objective OPEN ACCESS Citation: Zheng F, Wen H, Shi L, Wen C, Wang Q, Yao S (2023) Incidence of postpartum hemorrhage based on the improved combined method in evaluating blood loss: A retrospective cohort study. PLoS ONE 18(7): e0289271. https://doi.org/ 10.1371/journal.pone.0289271 Editor: Fadhlun Alwy Al-beity, MUHAS: Muhimbili University of Health and Allied Sciences, UNITED REPUBLIC OF TANZANIA In view of the current clinical inaccuracies and underestimations of postpartum hemorrhage amount, this study aims to investigate the incidence, etiology, clinical characteristics of postpartum hemorrhage in different modes of delivery based on the combination of volumetric method, gravimetric method and area method in evaluating blood loss. Design This retrospective cohort study was conducted in Hangzhou Women’s Hospital from January 2020 to June 2021, including 725 cases of postpartum hemorrhage among 18,977 parturients. Based on different modes of delivery, the participants were divided into three groups: vaginal delivery, forceps delivery, and cesarean section, for comparison. Received: May 7, 2022 Accepted: July 16, 2023 Published: July 28, 2023 Copyright: © 2023 Zheng et al. This is an open access article distributed under the terms of the Creative Commons Attribution License, which permits unrestricted use, distribution, and reproduction in any medium, provided the original author and source are credited. Data Availability Statement: All relevant data are within the paper and its Supporting Information files. Funding: The author(s) received no specific funding for this work. Competing interests: The authors have declared that no competing interests exist. Methods Using an improved combined assessment method for blood loss, we retrospectively analyzed a cohort of parturients with postpartum hemorrhage who underwent vaginal delivery, forceps delivery, or cesarean section and were hospitalized in Hangzhou Women’s Hospital from January 2020 to June 2021. Results (1) Among the 18,977 parturients, 725 cases of postpartum hemorrhage occurred, with an incidence rate of 3.8%, and severe postpartum hemorrhage accounted for 0.4% of the cases. (2) The incidence of postpartum hemorrhage was significantly higher in the forceps delivery group than in the vaginal delivery group (χ2 = 19.27, P<0.001), while the incidence of severe postpartum hemorrhage was significantly higher in the cesarean section group than in the vaginal delivery group (χ2 = 8.71, P = 0.003). (3) The causes of postpartum hemorrhage were statistically different among the different delivery modes, with varying PLOS ONE | https://doi.org/10.1371/journal.pone.0289271 July 28, 2023 1 / 12 PLOS ONE Analysis of PPH based on the improved combined method in evaluating blood loss underlying factors (P<0.001). (4) Patients with postpartum hemorrhage in different delivery modes showed statistically significant differences in age, body mass index (BMI), birth weight, gestational age, gravidity, parity, the decline of postpartum peripheral blood hemoglobin concentration, and estimated blood loss (P<0.05). (5) The proportion of blood transfusion was significantly higher in the cesarean section group than in the vaginal delivery and forceps delivery groups (χ2 = 231.03, P<0.001). Limitations This study is a single-center retrospective study, which may have led to selection bias in case selection. Additionally, the implementation of the combined three blood loss assessment methods may not have been strictly followed in all cases. Moreover, due to the mixing of bleeding with amniotic and irrigation fluids, the accuracy of evaluation may have been affected, leading to the possibility of inaccuracy of blood loss. Conclusions Forceps delivery and cesarean section increase the risk of postpartum hemorrhage, but forceps delivery does not significantly increase the incidence of severe postpartum hemorrhage. Uterine atony remains the leading cause of postpartum hemorrhage, while birth canal laceration and placental factors are the second most common causes of postpartum hemorrhage in forceps delivery and cesarean section, respectively. In this study, the volumetric method, gravimetric method and area method were combined to quantitatively assess postpartum hemorrhage amount. The combined method has strong clinical practicability and is less affected by subjective factors, although it also has limitations. In the future, we still need to focus on the early prediction and identification of postpartum hemorrhage, and further improve the quantitative assessment of postpartum blood loss. Introduction Postpartum hemorrhage (PPH) is a serious obstetric complication that occurs and develops so rapidly, which is still a leading cause of maternal death in China [1]. It can be accompanied by serious maternal complications, such as hypovolemic shock, disseminated intravascular coagulation (DIC), acute renal failure, acute respiratory distress, Sheehan syndrome; loss of fertility has also been reported [2, 3]. In the past 10 years, the incidence of PPH in some developed countries was still rising, mainly due to the increased incidence of uterine atony [4]. It is also positively correlated with labor induction, prenatal oxytocin use, and the increasing cesarean section rate [5]. A meta-analysis involved multiple countries in 2012 indicated that the incidence of PPH fluctuated from 7.2% to 25.7% (with an average of approximately 10.8%).The study also pointed out that the incidence of PPH was affected by the regions and the methods of blood loss assessment [6]. At present, clinical underestimation of postpartum blood loss is still common [7–10], and some studies indicated that inaccurate estimates of actual blood loss after birth occurred by healthcare providers are the main reason for the delayed bleeding response [11–13]. The traditional visual method to estimate blood loss during childbirth and postpartum is subjective and not accurate enough [14–16]. Quantitative measurements of blood loss such as spectrophotometry [17, 18], gravimetric measurement [9], objective PLOS ONE | https://doi.org/10.1371/journal.pone.0289271 July 28, 2023 2 / 12 PLOS ONE Analysis of PPH based on the improved combined method in evaluating blood loss quantification with a novel birthing drape using the volumetric method [8, 19], hematocrit [20, 21] are more accurate than the visual method. However, no method of quantifying blood loss has been proven to be optimal by the (...truncated)