Objective. To investigate the resuscitative efficacy of haemoglobin vesicles (HbVs) for severe postpartum haemorrhage (PPH) using pregnant rabbits. Design: Animal research study Setting: Animal laboratory, National Defense Medical College, Japan Population: Twenty-five female New Zealand white rabbits at late gestation Methods. Pregnant rabbits underwent caesarean section; uncontrolled haemorrhage was induced by transecting the uterine artery to establish a severe PPH model. During the first 30 min (or until the bleeding volume reached 100 mL), all rabbits received 6% hydroxyethyl starch (HES) infusion. Thereafter, rabbits received any of the three isovolemic fluid resuscitations every 5 min: red blood cells (RBCs) with platelet-poor plasma (RBC/PPP) (vol/vol=1:1, n=8), 6% HES (n=7), or HbVs with 25% human serum albumin (vol/vol=4:1, n=10). After 60 min (or when the bleeding volume reached 200 mL), we performed surgical haemostasis and monitored the rabbit survival for 12 hours. Main Outcome Measures: Survival time for severe postpartum haemorrhage Results. During the first 30 min, all rabbits showed severe anaemia (Hb <6 g/dL) that eventually developed to severe PPH. All rabbits that received only HES infusion died within 6 hours, whereas those that received RBC/PPP transfusion survived. Furthermore, 8 of the 10 rabbits received HbV infusion 6 hours after PPH. Overall survival of HbV group was markedly improved compared with that of HES group (p=0.01) but was significantly worse than that of RBC/PPP group (p<0.01). Conclusions. HbV infusion for severe PPH effectively prevented lethal haemorrhagic shock in a pregnant rabbit model, making it a feasible alternative modality.