Department of Obstetrics and Gynaecology, United Christian Hospital, Kowloon, Hong Kong.
J Obstet Gynaecol. 2020 May;40(4):479-484. doi: 10.1080/01443615.2019.1631769. Epub 2019 Sep 3.
The objective of this study was to evaluate the value of clinical and ultrasound risk factors in predicting severe postpartum haemorrhage (PPH) (≥1.5 L) in pregnancies undergoing caesarean section for placenta praevia. This cohort consists of all cases of placenta praevia undergoing caesarean delivery over a period of 5 years in a service unit. Patients and their delivery data were retrieved from an obstetric database. Ultrasound features were prospectively recorded before caesarean section. The incidence of caesarean section for placenta praevia was 0.98% ( = 215). Of these, 12.1% ( = 26) had severe PPH. A logistic regression model showed that major praevia, antepartum haemorrhage before delivery and anterior placenta remained significant factors associated with severe PPH. The sensitivity/specificity and positive/negative predictive value of the model are 96.2%, 59.8%, 24.8% and 99.1%, respectively. Our model had high sensitivity and negative predictive value for severe PPH during caesarean section for placenta praevia.Impact statement Placenta praevia is known to be one of the leading causes of severe PPH. Many risk factors have been associated with severe bleeding during caesarean section for placenta praevia. However, the importance of individual factors in predicting pregnancy outcome remains controversial. Our model includes only three simple parameters, namely the presence of significant antepartum haemorrhage (APH) from the history, and anterior or posterior placenta and major or minor praevia from ultrasound findings, but could predict up to 96.2% of all severe PPH. More importantly, the absence of APH, a posterior minor praevia, was associated with a negative predictive value of 99.1% of severe PPH, implying that such cases could be treated as 'normal' low risk caesarean sections. This simple model would allow differential pre-operative counselling of patients on risks and complications, planning and preparation of operation, allocation of staff as well as in contingency measures to be taken during operation. The establishment of a differential protocol for placenta praevia based on these simple risks factors and a prospective trial of such a protocol is suggested.
本研究旨在评估临床和超声危险因素在预测前置胎盘剖宫产中重度产后出血（PPH）（≥1.5L）中的价值。该队列包括在一个服务单位的 5 年内行剖宫产术治疗前置胎盘的所有病例。从产科数据库中检索患者及其分娩数据。在剖宫产术前前瞻性记录超声特征。前置胎盘行剖宫产术的发生率为 0.98%（215 例）。其中，12.1%（26 例）发生严重 PPH。逻辑回归模型显示，主要前置胎盘、产前出血和前位胎盘仍然是与严重 PPH 相关的显著因素。该模型的灵敏度/特异性、阳性/阴性预测值分别为 96.2%、59.8%、24.8%和 99.1%。我们的模型对前置胎盘剖宫产术中严重 PPH 具有较高的灵敏度和阴性预测值。
前置胎盘是导致严重 PPH 的主要原因之一。许多危险因素与前置胎盘剖宫产术中严重出血有关。然而，个体因素对预测妊娠结局的重要性仍存在争议。我们的模型仅包含三个简单的参数，即病史中存在显著产前出血（APH），超声检查中存在前位或后位胎盘以及主要或次要前置胎盘，但可以预测高达 96.2%的所有严重 PPH。更重要的是，不存在 APH、后位小前置胎盘与严重 PPH 的阴性预测值为 99.1%相关，这意味着此类病例可视为“正常”低风险剖宫产。该简单模型可对患者进行术前风险和并发症的咨询、手术计划和准备、人员分配以及手术期间的应急措施进行差异化处理。建议根据这些简单的风险因素制定前置胎盘的差异化方案，并对该方案进行前瞻性试验。
