2025 Southeastern Residency Conference

Title: Evaluating The Incidence of Adverse Effects Associated with High-Dose Intrapartum Vancomycin Administration for Group B Strep Prophylaxis


Authors: Jesse Klus, Kendall Heetdirks, Tanya Makhlouf


Objective: Evaluate the incidence of acute kidney injury and other pertinent adverse reactions in pregnant patients receiving high-dose vancomycin for intrapartum Group B Strep prophylaxis 


Self Assessment Question: MJ is a 29 YOF G1P0 at 39w5d who presents in active labor. She has had an uncomplicated pregnancy course thus far. She was found to be GBS positive and does have a high-risk allergy to penicillin. Clindamycin susceptibilities are unknown Her Scr is 0.89 and she weighs 70 kg. Which of the following would be the best regimen for GBS prophylaxis? 
A.Vancomycin 1000 mg IV Q12h
B.Clindamycin 900 mg IV Q8h
C.Cefazolin 2000 mg IV Q8h
D.Vancomycin 20 mg/kg IV Q8h


Background/Purpose: Prior to the implementation of intrapartum Group B Strep (GBS) prophylaxis, GBS was the most common cause of neonatal sepsis. Approximately 50% of women who are colonized with GBS will transmit the bacteria to their newborn either during the intrapartum period or after rupture of membranes. Without the use of prophylactic antibiotics in the intrapartum period, about 1-2% of newborns exposed to GBS develop early onset infections. The American College of Obstetricians and Gynecologists (ACOG) recommends administering GBS prophylaxis to women who have either known or unknown GBS colonization to decrease the rate of transmission to the neonate. Penicillin G is the preferred agent for GBS prophylaxis; however, cefazolin can be utilized in patients who have a low-risk penicillin allergy and vancomycin is preferred in patients who have a high-risk penicillin allergy and either known or unknown resistance to clindamycin. In June 2019, the recommended vancomycin dose was increased from 1000 mg IV every 12 hours to 20 mg/kg/dose (max 2000 mg) IV every 8 hours based on studies evaluating maternal and neonatal vancomycin levels. The purpose of this study was to evaluate the incidence of adverse effects associated with high-dose vancomycin for GBS prophylaxis during labor. 
 
Methodology: This was a multi-center, prospective, IRB approved, cohort study conducted at the Moses Cone Women’s and Children’s Center and Alamance Regional Medical Center in Greensboro, NC. On October 4, 2023, both centers adopted the vancomycin 20 mg/kg/dose every 8 hours dosing regimen for GBS prophylaxis in the intrapartum period. Patients were included in if their gestational age was at least 23 weeks and received at least one dose of vancomycin for GBS prophylaxis from October 1, 2022, to November 1, 2024. Patients were excluded if they received antibiotics for another indication, received an antibiotic for GBS prophylaxis other than vancomycin, had known intrauterine fetal demise, or were dialysis dependent. The primary objective was the incidence of acute kidney injury (AKI) following vancomycin dosing, as defined by an increase in serum creatinine of at least 0.3 mg/dL within 48 hours. Secondary objectives further evaluated the safety of high-dose vancomycin. Results were evaluated utilizing Fisher’s Exact and two sample T-tests.  
 
Results: A total of 93 patients were included in the analysis. There were 2 incidences of AKI in the post-group compared to none in the pre-group (p = 0.19). There was no statistically significant difference seen in the rates of GBS infection of the newborn and vancomycin flushing reactions between groups. More doses of vancomycin were given in the post-group (2.0 vs 1.7, p = 0.14) and the dose of vancomycin was higher in the post-group (1625 mg vs 1000 mg, p < 0.001). There were no trough levels obtained in the pre-group and five trough levels obtained in the post-group. The majority of trough levels drawn in the post-group were supratherapeutic.
 
Conclusions: High-dose vancomycin was not associated with a significant increase in AKI.   The difference seen in trough levels obtained between groups can be attributed to both increased dosing frequency in the high-dose group and overall short labor durations, making obtaining trough levels less feasible. While most of the trough levels obtained in the high-dose group were supratherapeutic, there was no indication that this resulted in increased adverse events. Additionally, the new dosing regimen provided adequate protection against GBS in newborns, as indicated by low infection rates. This evaluation demonstrates that high-dose vancomycin is a safe regimen for GBS prophylaxis in the intrapartum period. Larger evaluations are necessary to confirm the findings of this study.