Intramuscular versus intravenous oxytocin for reducing blood loss after vaginal birth

Oxytocin given to a woman during or immediately after the birth of her baby (prophylactically) is effective in reducing excessive bleeding after vaginal birth. There is no reliable research to show whether giving the oxytocin into a muscle or vein makes any difference to the effectiveness of the oxytocin or the health of the mother and baby.

The third stage of labour is the period between the birth of the baby and the delivery of the placenta. Excessive blood loss during this period or immediately thereafter can be prevented by giving oxytocin, which is a drug that makes the womb contract to close the blood vessels in the placenta and helps it separate from the wall of the uterus. When injected into a vein, oxytocin starts to work almost immediately whereas it takes some three to seven minutes when injected into a muscle. Oxytocin given into a vein has been reported to occasionally cause serious side effects such as a sudden drop in blood pressure and an increase in heart rate, particularly when given rapidly in a small amount of solution (undiluted). The method involved in injecting oxytocin into a muscle takes much less time than those involved for injecting it into a vein. It is also more convenient for the provider, requires relatively less skill and thus can be given by providers with limited skills. This review found no randomised controlled trials to show whether giving oxytocin into a muscle or vein is better than the other in terms of potential benefits, side effects or risks to the mother or the baby.

Authors' conclusions: 

There is no evidence from randomised trials to evaluate the comparative benefits and risks of intramuscular and intravenous oxytocin when given to prevent excessive blood loss after vaginal birth. Randomised trials with adequate design and sample sizes are needed to assess whether the route of prophylactic oxytocin after vaginal birth affects maternal or infant outcomes. Such trials should be large enough to detect clinically important differences in major side effects reported in observational studies and also to consider the acceptability of the intervention to mothers and providers as important outcomes.

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Background: 

There is a general agreement that oxytocin given either through the intramuscular or intravenous route is effective in reducing postpartum blood loss. However, it is unclear whether the subtle differences between the mode of action of these routes have any effect on maternal and infant outcomes.

Objectives: 

To determine the comparative effectiveness and safety of oxytocin administered intramuscularly or intravenously for prophylactic management of the third stage of labour after vaginal birth.

Search strategy: 

We searched the Cochrane Pregnancy and Childbirth Group’s Trials Register (31 December 2011).

Selection criteria: 

Randomised trials comparing intramuscular with intravenous oxytocin for prophylactic management of the third stage of labour after vaginal birth. We excluded quasi-randomised trials.

Data collection and analysis: 

Two review authors planned to independently assess trials for inclusion, assess risk of bias and extract data.

Main results: 

The search strategies identified no trials for consideration but we identified one ongoing study.

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