The increasing role of a retained placenta in postpartum blood loss: a cohort study.

A retained placenta was shown to be a strong predictor of quantity of blood loss and duration of the third stage of labour a weak predictor of quantity of blood loss. The predictive power of the third stage of labour was further reduced in the multivariate analysis when including retained placenta in the model. There was an increase in the role of a retained placenta depending on the cutoff used to define postpartum haemorrhage, increasing from 12% in cases of blood loss ≥ 500 ml to 53% in cases of blood loss ≥ 2000 ml CONCLUSION: The predictive power of duration of the third stage of labour in regard to postpartum blood loss was diminished by the influence of a retained placenta. A retained placenta was, furthermore, present in the majority of most severe cases.