Oxytocin by I/V route more effective in prevention of postpartum hemorrhage

The administration of intravenous oxytocin for the third labor stage results in less frequent blood transfusion, severe postpartum hemorrhage (PPH), admission to a high dependency unit as compared to intramuscular oxytocin, and fewer side effects.

Nita Adnan, clinical lecturer, Trinity College, University of Dublin & Coombe Women & Infants University Hospital, Dublin, Ireland, and colleagues conducted the study to determine whether intravenous oxytocin is more effective than intramuscular oxytocin at preventing postpartum hemorrhage at vaginal delivery.

For this double-blind placebo-controlled randomized trial women were allocated to an intravenous bolus of oxytocin (10 IU in 1 mL given slowly over one minute) and placebo intramuscular injection (1 mL 0.9% saline) or an intramuscular bolus of oxytocin (10 IU in 1 mL) and placebo intravenous injection (1 mL 0.9% saline given slowly over one minute) at vaginal delivery.

The participants included 1075 women aged 18 years or older, at term with a singleton pregnancy who were aiming for a vaginal delivery with an actively managed third stage of labor.

The primary outcome was postpartum hemorrhage (PPH, measured blood loss ≥500 mL). Secondary outcomes were severe PPH (measured blood loss ≥1000 mL), need for blood transfusion, admission to a high dependency unit, and side effects to oxytocin.

Key Findings:

• The incidence of PPH was not significantly lower in the intravenous group (18.8%, 97/517) compared with an intramuscular group (23.2%, 120/518).


• The incidence of severe PPH, however, was significantly lower in the intravenous group (4.6%, 24/517) compared with intramuscular group (8.1%, 42/518): 0.54 (0.32 to 0.91) as was the need for blood transfusion (1.5% v 4.4%, 0.31, 0.13 to 0.70) and admission to a high dependency unit (1.7% v 3.7%, 0.44, 0.20 to 0.98).


• The number needed to treat to prevent one case of severe PPH was 29 (95% confidence interval 16 to 201) and to prevent one case of blood transfusion was 35 (20 to 121).


• The incidence of side effects to oxytocin was not increased in the intravenous group compared with an intramuscular group (4.1% v 5.2%, 0.75, 0.42 to 1.35).

"PPH is common, even in women apparently at low risk. Our findings support the use of intravenous oxytocin rather than intramuscular oxytocin in terms of preventing severe PPH and the need for blood transfusion, with the potential to prevent mortality if implemented globally in developing world settings," concluded the authors.