| Methods |
5‐arm placebo‐controlled randomised trial |
| Participants |
75 women were randomised in a hospital setting in the USA. The population comprised women of any parity, a singleton pregnancy, at high risk for PPH, who delivered by elective caesarean section. Exclusion criteria comprised women with active labour, ruptured membranes, drug allergy, multiple pregnancy, significant obstetric disease, risk factors for PPH (abnormal placentation, fibroids, previous PPH, previous classical uterine incision), coagulopathy or thrombocytopenia. |
| Interventions |
Placebo versus 5, 3, 1, or 0.5 IU of oxytocin administered by an IV bolus |
| Outcomes |
The study recorded the following outcomes: additional uterotonics; transfusion; blood loss (mL); nausea; vomiting; tachycardia; hypotension. |
| Notes |
Contact with study authors for additional information: yes. Additional data from authors: no |
| Risk of bias |
| Bias |
Authors' judgement |
Support for judgement |
| Random sequence generation (selection bias) |
Low risk |
Randomised using Microsoft Excel‐generated random number allocations |
| Allocation concealment (selection bias) |
Unclear risk |
Used opaque envelopes containing group assignments |
| Blinding of participants and personnel (performance bias)
All outcomes |
Low risk |
Quote: "The obstetrician and anaesthetist involved in each case were blinded to the oxytocin dose assignments". |
| Blinding of outcome assessment (detection bias)
All outcomes |
Unclear risk |
Assessor blinding was not reported. |
| Objective assessment of blood loss |
High risk |
Investigators appraised blood loss quote: "by estimating blood collected by suction and by calculating the weight of blood on surgical swabs". |
| Incomplete outcome data (attrition bias)
All outcomes |
Low risk |
Quote: "75 patients were enrolled, and 74 patients completed the study; 1 patient was excluded due to protocol violation (obstetrician request for supplemental oxytocin despite adequate uterine tone)". |
| Selective reporting (reporting bias) |
Unclear risk |
The protocol of the study was unavailable for verification. |
| Intention to treat analysis |
High risk |
Those who withdrew from the study after randomisation were not included in the analysis. |
| Funding source |
Low risk |
The study was supported by funding from the Department of Anesthesia of the Stanford University School of Medicine (the institution of the authors). |
