Incidence of Immediate Postpartum Hemorrhages in French Maternity Units: a Prospective Observational Study (HERA Study)

Background: Most estimates of postpartum hemorrhage (PPH) are calculated from studies that use administrative or medical birth databases, and only a few from prospective observational studies. Our principal objective was to estimate the incidence of PPH according to their severity (mild or severe) in vaginal deliveries (>500 mL, ≥1000 mL) and cesareans (>1000 mL and ≥1500 mL). The secondary objectives were to describe the incidence of PPH according to maternity unit characteristics, causes, and types of PPH management.

Methods: This prospective observational study took place in French maternity wards. Women who gave birth at a term ≥ 22 weeks were eligible for the study. 182 maternity units participated in a study with prospective data collection from 1 February, 2011, to 31 July, 2011. The main outcome measure was PPH incidence.

Results: PPH incidence after vaginal delivery was 3.36 % [95 % CI: 3.25-3.47 %] and after cesareans 2.83 % [95 % CI: 2.63-3.04 %]. The incidence of severe PPH after vaginal delivery was 1.11 % [95 % CI: 1.05-1.18 %] and after cesareans 1.00 % [95 % CI: 0.88-1.13 %]. This incidence rate varied according to maternity unit characteristics. The principal cause of PPH for both modes of delivery was uterine atony (57.7 % for vaginal births and 66.3 % for cesareans). Vascular embolization was more frequent among women with cesareans (10.0 vs. 2.9 %), who also required transfusions more often (44.4 vs 12.7 %).

Conclusions: The incidence of PPH was lower than the rate expected from the literature. Effective treatment of uterine atony and optimizing the identification of blood loss remain important priorities.