Thurn L, et al. - Researchers performed a population-based cohort study of obstetric patients for assessing the incidence, trends over time, and risk factors for massive blood transfusions in this population. In addition, they appraised transfusion ratios in relation to massive transfusion. From the Swedish National Medical Birth Registry (1990–2011), they evaluated data on 517,874 pregnancies and deliveries. Two hundred seventy-seven women required massive blood transfusion, for an incidence of 5.3 per 10,000 deliveries; these increased by 30% between the first and the second half of the study period. They identified the highest increased risk for women with abnormal placentation. They emphasize improving antenatal awareness of these women at risk so that management could be improved and the rate of massive transfusion could be reduced among them.