BACKGROUND AND PURPOSE:

• Arrest of labor is associated with higher risk for PPH following cesarean delivery
• Balki et al. (Obstetrics & Gynecology, 2021) evaluated whether prophylactic administration of oxytocin in combination with other uterotonics (ergonovine or carboprost) was more effective than oxytocin alone in reducing the need for additional uterotonics among women undergoing cesarean delivery for arrest of labor

METHODS:

• Double-blind, three-arm randomized controlled trial
  • All investigators, participants and clinicians were blinded to study medication allocation
• Participants
  • Cesarean delivery for labor arrest
  • Epidural analgesia
  • Received ≥4 hours of oxytocin for labor augmentation
• Interventions (1:1:1 randomization)
  • Oxytocin alone (5 units IV) + IM placebo
  • Oxytocin (5 units IV) + ergonovine (0.25 mg IV) + IM placebo  
  • Oxytocin (5 units IV) + carboprost (0.25 mg IM)
• Study design
  • Uterotonics given immediately after delivery | All patients received additional maintenance infusion of oxytocin 40 milliunits/minute
  • Additional uterotonics were administered if necessary
• Statistical analysis
  • Sample size: For 80% power to reject the null hypothesis and an alpha of 0.025 (to account for multiple comparisons), a sample size of 34 per group was required | 35 per group were recruited to account for drop out
  • Assumptions based on previous study where 57% oxytocin alone group vs 21% in oxytocin plus ergonovine group required  additional uterotonics
• Primary outcome
  • Intraoperative need for additional uterotonics
• Secondary outcomes
  • Uterine tone, calculated blood loss, and side effects

RESULTS:

• 100 participants were analyzed
  • Oxytocin alone: 35 individuals
  • Oxytocin plus ergonovine: 33
  • Oxytocin plus carboprost: 32
• There was no difference in the requirement of additional intraoperative uterotonics across groups (P = 0.932)
  • Oxytocin alone: 37%
  • Oxytocin plus ergonovine: 33%
  • Oxytocin plus carboprost: 34%
• Uterine tone and calculated blood loss were similar across groups
• Incidence of nausea or vomiting was higher in the combined groups vs oxytocin alone
  • Oxytocin alone: 51%
  • Oxytocin plus ergonovine: 85%; OR 5.3 (95% CI, 1.7 to 16.9; P = 0.003)
  • Oxytocin plus carboprost: 72%; OR 2.4 (95% CI, 0.9 to 6.7; P = 0.086)

CONCLUSION:

• Adding ergonovine or carboprost to prophylactic oxytocin did not reduce the need for additional uterotonics in women undergoing cesarean delivery for arrest of labor following delivery
• The authors conclude

We suggest that uterotonic drugs such as ergonovine or carboprost only be used when necessary, particularly given the high incidence of side effects with their prophylactic use

Learn More – Primary Sources:

Prophylactic Administration of Uterotonics to Prevent Postpartum Hemorrhage in Women Undergoing Cesarean Delivery for Arrest of Labor: A Randomized Controlled Trial

Related ObG Topics:

What are the Possible Causes of a PPH that is Unresponsive to First Line Uterotonics?

Cochrane Review 2018: Uterotonic Agents for PPH Prophylaxis

Is Carbetocin More Effective than Oxytocin for PPH Prevention During Elective Cesarean?