Undiagnosed abnormal postpartum blood loss: Incidence and risk factors

PLoS One. 2018 Jan 10;13(1):e0190845. doi: 10.1371/journal.pone.0190845. eCollection 2018.

Abstract

Background: We aimed to evaluate the incidence of undiagnosed abnormal postpartum blood loss (UPPBL) after vaginal delivery, identify the risk factors and compare them to those of postpartum haemorrhage (PPH).

Method: The study population included women who participated in a randomized controlled trial of women with singleton low-risk pregnancy who delivered vaginally after 35 weeks' gestation (n = 3917). Clinical PPH was defined as postpartum blood loss ≥ 500 mL measured by using a collector bag and UPPBL was defined by a peripartum change in haemoglobin ≥ 2 g/dL in the absence of clinical PPH. Risk factors were assessed by multivariate multinomial logistic regression.

Results: The incidence of UPPBL and PPH was 11.2% and 11.0% of vaginal deliveries, respectively. The median peripartum change in Hb level was comparable between UPPBL and PPH groups (2.5 g/dL interquartile range [2.2-3.0] and 2.4 g/dL IQR [1.5-3.3]). Risk factors specifically associated with UPPBL were Asian geographical origin (adjusted OR [aOR] 2.3, 95% confidence interval [CI] 1.2-4.2; p = 0.009), previous caesarean section (aOR 3.4, 2.1-5.5; p<0.001) and episiotomy (aOR 2.6, 1.8-3.6; p<0.001). Risk factors for both UPPBL and PPH were primiparity, long duration of labour, instrumental delivery and retained placenta.

Conclusion: Undiagnosed abnormal postpartum blood loss is frequent among women giving birth vaginally and has specific risk factors. The clinical importance of this entity needs further confirmation, and the benefit of systematic or targeted prevention strategies needs to be assessed.

Publication types

  • Multicenter Study
  • Randomized Controlled Trial
  • Research Support, Non-U.S. Gov't

MeSH terms

  • Adult
  • Anemia / epidemiology
  • Anemia / etiology
  • Diagnostic Errors
  • Female
  • Humans
  • Incidence
  • Logistic Models
  • Multivariate Analysis
  • Postpartum Hemorrhage / diagnosis
  • Postpartum Hemorrhage / epidemiology*
  • Postpartum Hemorrhage / etiology*
  • Postpartum Period
  • Risk Factors

Grants and funding

Data originate from the TRACOR trial (ClinicalTrials.gov identifier NCT01044082). This study was approved by the Paris-Ile de France III Committee for the Protection of Research Subjects (Ethics Committee) in September 2009. The TRACOR trial was supported by the French Ministry of Health under its clinical research hospital program (contract no. P081206). The funding source had no role in the study design, writing of the report, or the decision to submit the paper for publication.