A meta-analysis of the effects of intramuscular and intravenous injection of oxytocin on the third stage of labor.

BACKGROUND

Clinical studies and trials have shown that oxytocin can effectively reduce postpartum bleeding, whether by intramuscular (IM) injection or intravenous (IV) injection. These two methods are widely used in the prevention and treatment for the third stage of childbirth. However, it is unclear whether the subtle differences between the mode of these routes have any effect on maternal outcomes.

OBJECTIVES

To systematically evaluate the efficacy and safety of oxytocin administered intramuscularly or intravenously for prophylactic management of the third stage of labor after vaginal birth.

METHODS

Computerized retrieval of PubMed, the Cochrane Library, Web of Science, Embase, and ClinicalTrials.gov was conducted to collect randomized controlled trials (RCT) on the effects of IM and IV oxytocin on the third stage of labor. After independent literature screening, data extraction and evaluation of the bias risk of included studies by two evaluators, RevMan 5.3 software was used for a meta-analysis.

RESULTS

Six studies with 7734 women were included in this study. Meta-analysis results showed that: the severe postpartum hemorrhage (PPH) rate [risk ratio (RR) 1.54, 95% confidence interval (95% CI) 1.08-2.20, P = 0.02], PPH rate (RR 1.31, 95% CI 1.11-1.55, P = 0.001), incidence of blood transfusion (RR 2.30, 95% CI 1.35-3.93, P = 0.002) and the need of manual removal of placenta (RR 1.44, 95% CI 1.05-1.96, P = 0.02) for IM group were higher than IV group, but there were no significant differences in the use of additional uterotonics (P = 0.31) and the incidence of serious maternal morbidity and adverse effects between two groups. None of the included studies reported maternal death.

CONCLUSION

For clinical practice, intravenous injection oxytocin 10 IU may be a good, safe option in the management of the third stage of labor. Medical conditions, available resources, adverse effects, and women' s preferences should also be considered. If an IV line is already in place at delivery, IV administration may be preferable to IM injection.