Effect of an oxytocin standardization regimen on postpartum hemorrhage: does mode of delivery matter?

To compare the effect of implementing a standardized oxytocin management protocol (SOP) in the third stage of labor on the frequency of postpartum hemorrhage (PPH), transfusion amounts, and delivery mode. A retrospective cohort study conducted at a single level-three urban perinatal center. Obstetrical patients ≥ 24 weeks gestational age with PPH between January 2010 to June 2015 were evaluated via electronic medical record database (Intellispace Perinatal). PPH was defined as uterine atony or hemorrhage with the use of an uterotonic agent, uterine tamponade, uterine artery embolization, blood transfusion, or hysterectomy. PPH rates were compared before (PREP January, 2010 to August 28, 2012) and after (POSTP August 28, 2012 at to June 2015) implementation of a SOP for PPH prophlaxis (60 units over 5 hours). Blood transfusion amounts were dichotomized by ±≥ 4 units of packed red blood cells intra-operative or postpartum (pRBCs). The PREP group provided 80% power to detect an effect size of 0.50 between the two strata via two-sided testing. The POSTP group provided 80% power to detect an effect size of 0.61 between the two strata via two-sided testing. 16,811 women were included in the final analysis. Significant differences were noted between the PREP group (n=7,791) and POSTP group (n=9,020) in the demographic categories of age (p=0.001), race (p=0.001), insurance type (p=0.001), and delivery type (p=0.001). Vaginal and cesarean deliveries were significantly different (p<0.001) between the PREP group 4,775 (61.3%); 2,590 (33.2%) and POSTP group 5,767 (63.9%); 2716 (30.1%), respectively (table). There were significant reductions of PPH in the adjusted relative risk between the PREP and POSTP groups. The PREP group with transfusions ≥ 4 pRBCs were significantly different (p<0.001) between delivery modes of vaginal 32 (18.8%) and cesarean 25 (78.1%) versus transfusions <4 pRBCs between delivery modes of vaginal 4,769 (61.5%) and cesarean 2,565 (33.1%). The POSTP group with transfusions ≥ 4 pRBCs were significantly different (p<0.001) between delivery modes of vaginal 4 (19%) and cesarean 14 (66.7%) versus transfusions <4 pRBCs between delivery modes of vaginal 5,763 (64%) and cesarean 2,702 (30%). Implementation of a SOP for PPH prophylaxis reduced the rate of PPH in specific delivery modes along with pRBCs transfusion amounts.