Haematological parameters associated with postpartum haemorrhage after vaginal delivery: Results from a French cohort study

Background: Immediate postpartum haemorrhage (PPH) is a major, feared and often unpredictable issue. Besides many clinical risk factors, some biological parameters could also be predictive of PPH.

Objective: To study simple and easily accessible haematological parameters as potential risk factors for PPH after vaginal delivery.

Methods: All women who had a vaginal delivery between April 1, 2013 and May 29, 2015 in the maternity ward of Brest University Hospital (France) were included, after oral informed consent obtained. Clinical data were collected by obstetricians or midwives during antenatal care visits, labour and delivery, and recorded by trained research assistants. Haematological variables, including immature platelet fraction, were measured from a blood sample systematically collected at the entrance in the delivery room. PPH, measured with a graduated collector bag, was defined as blood loss of at least 500 ml.

Results: 2742 women were included. PPH occurred in 141 (5%) women. Seven clinical factors were independently associated with PPH: pre-eclampsia (OR 5.85, 95%CI 2.02, 16.90), multiple pregnancy (OR 3.28, 95%CI 1.21, 8.91), assisted reproduction (OR 2.75, 95%CI 1.45, 5.20), antepartum bleeding (OR 2.15, 95%CI 1.24,3.73), post-term delivery (OR 1.93, 95%CI 1.17, 3.17), obesity (OR 2.95, 95%CI 1.76, 4.93) and episiotomy (OR 2.51, 95%CI 1.63, 3.74). Three haematological factors were additionally identified as independent risk factors for PPH: platelets < 150 Giga/L (OR 2.98, 95%CI 1.63, 5.46), fibrinogen < 4.5 g/l (OR 1.86, 95%CI 1.21, 2.87) and APTT ratio ≥ 1.1 (OR 2.16, 95%CI 1.31, 3.57). Immature platelet fraction was not associated with PPH.

Conclusion: Besides classical clinical risk factors, this study identifies simple haematological parameters as risk factors for PPH.