Is It in Your Blood: Does Blood Type O Increase the Risk of Early Postpartum Hemorrhage? [21M

Abstract

INTRODUCTION: Patients with type O blood have been demonstrated to have lower von Willebrand levels than other ABO types. We evaluated whether O blood type is associated with an increased risk of early postpartum hemorrhage (PPH). METHODS: We performed an Institutional Review Board approved retrospective cohort study of women aged 18-45 who had a vaginal or cesarean delivery of a live-born singleton infant at our institution from January 1, 2018 to December 31, 2018. The quantitative blood loss (QBL) from delivery and rates of early PPH were compared between patients with type O blood and those with non-type O blood. Early PPH was defined as 1,000 mL of blood loss or greater within 24 hours of delivery. Patient characteristics were compared. Chi square tests and student’s t-tests were used to assess for statistical significance. RESULTS: There were 9,990 patients included with 4,422 (44.3%) in the O group and 5,568 (55.7%) in the non-O group. The groups were similar with regard to age, parity, gestational age at delivery, mode of delivery, rate of induction, episiotomy use, delivery anesthesia type, and birth weight. There was a higher proportion of grand multiparity (parity of 5 or greater) in the non-O group (6.16% versus 5.01%, P=.02). Rates of early PPH were similar in the type O and non-O groups (7.78% versus 7.22%, P=.29). There was no significant difference in the mean QBL between the groups (450.9 mL versus 434.7mL, P=.75). CONCLUSION: In this analysis, O blood type was not associated with an increased risk for early PPH.