Is it possible to predict severe postpartum hemorrhage and the need for massive transfusion in placenta previa cases?

The aim was to construct a reliable working model for patients with placenta previa (PP) that aids in the prediction of postpartum bleeding potential with data from antenatal imaging studies using both ultrasound (US) and magnetic resonance imaging (MRI).

Forty-three patients with PP were evaluated initially with the US and then by 3-Tesla MRI. The Placenta Accreata Index (PAI) was used during the US evaluation in order to define the risks. Uterine bulging, heterogeneous signal, dark placental bands, focal interruption of myometrium and tenting of bladder wall were regarded as predictive criteria in MRI evaluation. The correlation between the findings from US and MRI studies and subsequent haemorrhage, < 1000 mL, > 1000 mL and severe haemorrhage ( > 2000 mL) and massive transfusion [ > 5 units of red blood cells (RBC)] were used to build this predictive model. The findings from the imaging studies were also confirmed histopathologically.

In the multivariate analysis of data from patients stratified by bleed size either < 1000 mL or > 1000 mL, none of the MRI and ultrasound findings were found to be predictive. The multivariate analysis was done using the second stratification cut-point of 2000 mL, in patients bleeding > 2000 mL PAI values [OR: 2.3 (1.4-3.8)] and overall MRI reported placenta accreata spectrum [OR: 4.9 (1.8-12.9)] were found to be predictive. While MRI findings were not discriminative between transfusion groups, grade 3 loculation on US examination was found to be predictive for the need of transfusion of > 5 units [OR: 67.5 (8.2-549.4)]. There were no cases needing hysterectomy.

Ultrasound and MRI findings in cases of PP can be helpful in predicting postpartum bleeding.