BACKGROUND AND PURPOSE:

• Charles et al. (BMC Pregnancy Childbirth, 2019) sought to determine the effectiveness and safety of 10 IU oxytocin administration techniques during the third stage of labor for PPH

METHODS:

• Open-label, three-arm, parallel, randomized controlled trial (RCT)
• Participants
  • Women delivering vaginally without exposure to pre-delivery uterotonics
• Randomization to the following groups
  • Intramuscular (IM) injection (in thigh)
  • Intravenous (IV) infusion
    • Oxytocin mixed in 500 mL fluid | Gravity-driven infusion through an 18g needle
  • Intravenous (IV) bolus
    • Directly in to port over 1 minute
  • Primary outcomes
    • Mean postpartum blood loss (recorded 1 hour after delivery, using an objective measuring system)
    • Proportion of women with postpartum blood loss ≥500 ml
  • Side effects also documented, as well as demographics, obstetrical and intrapartum history

RESULTS:

• 4,913 women were randomized
• 2,104 IM injection | 2,108 via IV infusion | 701 via IV bolus
• Compared to IM injection, mean blood loss was significantly reduced in IV arms
  • 5.9% less in the IV infusion arm (95% CI, -8.5, - 3.3)
  • 11.1% less in the IV bolus arm (95% CI, -14.7, - 7.8)
• Compared to IM injection, risk of postpartum blood loss ≥500 ml was significantly reduced with IV infusion
  • Risk of PPH ≥500 ml: 0.8% vs. 1.5%
  • Relative risk (RR) 0.50 (95% CI, 0.27, 0.91)
• Compared to IM injection, risk of postpartum blood loss ≥500 ml was reduced with IV bolus but not statistically significant
• No side effects were reported in any arm

CONCLUSION:

• IV oxytocin is more effective than IM injection in prevention of PPH in 3^rd stage of labor
• The authors acknowledge (1) lack of blinding and (2) lack of electrical IV pumps to be limitations
• Authors state

If an IV line is already in place at delivery, IV infusion or IV bolus administration of oxytocin may be preferable to IM injection in the third stage of labor

• Findings consistent with previous studies (see ‘Related ObG Topics’ below)

Learn More – Primary Sources:

Intramuscular injection, intravenous infusion, and intravenous bolus of oxytocin in the third stage of labor for prevention of postpartum hemorrhage: a three-arm randomized control trial.

Related ObG Topics:

Postpartum Hemorrhage – Medications to Treat Uterine Atony 

Latest Cochrane Review: What is the Most Effective Prophylactic Treatment for Postpartum Hemorrhage?

Postpartum Hemorrhage Prophylaxis: The World Health Organization Recommendations

Intramuscular or Intravenous Oxytocin to Prevent Postpartum Hemorrhage?