Hemorrhage-related maternal morbidity of secondary compared to primary postpartum hemorrhage

To compare a composite hemorrhage-related maternal morbidity in individuals with secondary to primary postpartum hemorrhage and treatment interventions utilized.

A retrospective case-control study of deliveries complicated by secondary postpartum hemorrhage was performed at a tertiary care center. To estimate a clinically relevant increase of 50 % in the composite maternal hemorrhage-related maternal morbidity (35-53 % absolute increase) in individuals with secondary postpartum hemorrhage, a correlation coefficient of 0.2, at an 80 % power with a p < 0.05 with a two-sided test would require 95 individuals with secondary postpartum hemorrhage be matched to 95 individuals with a primary postpartum hemorrhage. Logistic regression analysis was used to evaluate the outcome of the composite of hemorrhage-related maternal morbidity.

From January 2018 through December 2022, 33,026 deliveries occurred, and 94 individuals were identified that were admitted with secondary postpartum hemorrhage, 0.28 % of deliveries, 95 % confidence interval (CI) 0.21-0.35 %. The composite hemorrhage-related maternal morbidity was increased in individuals with secondary compared to primary postpartum hemorrhage, adjusted odds ratio (OR) 14.0, 95 % CI 4.6 to 42.2. Most individuals with secondary postpartum hemorrhage had a dilation and curettage 91.5 % (86/94). In individuals with secondary postpartum hemorrhage that underwent uterine evacuation, histology revealed 45.2 % (38/84) had retained placenta, and 20.2 % (17/84) subinvolution.

A composite maternal hemorrhage-related outcome is associated more often with secondary compared to primary postpartum hemorrhage and nearly all individuals with secondary postpartum hemorrhage undergo a dilation and curettage.