ObjectiveTo compare the effectiveness of rectal misoprostol with intramuscular oxytocin in the management of the third phase of labour. Materials and methodPatients to be treated with rectal misoprostol (group A) or intramuscular oxytocin (group B) were selected and randomised to attend delivery at the Central Hospital ‘Dr. Urquinaona’, Maracaibo, Venezuela. An evaluation was made of the general characteristics, changes in haemoglobin and haematocrit values, post-partum blood loss, and adverse effects. ResultsComplete data were obtained from 392 patients (195 from Group A and 197 from Group B), who were included in the final analysis. No significant differences were found between the groups with respect to the general characteristics (P=ns). No statistically significant differences were found in the mean values of haemoglobin and pre- and post-partum haematocrit (P=ns). There was a significant decrease in the duration of the third phase of labour in Group A compared to patients in Group B (P<.001). The estimated blood loss in patients in Group A was significantly lower (P<.05). It was observed that the patients in Group A had a tendency to a lower use of additional uterotonics (P<.05). Patients in Group A presented with a higher frequency of headache and shivering compared to patients in Group B (P<.05). ConclusionsMisoprostol administered rectally is effective in minimising blood loss and duration of the third phase of labour.