Severe postpartum haemorrhage and mode of delivery: a retrospective cohort study

Objective To examine the association between intended mode of delivery and severe postpartum haemorrhage. Design A retrospective cohort study. Setting Material from a nationwide study in Denmark. Population Danish women giving birth in 2001-08. Methods We compared use of red blood cell transfusion by intended mode of delivery in the total population (n = 382 266), in low-risk nulliparous women (n = 147 132) and in women with a previous caesarean delivery (n = 25 156). Main outcome measure Red blood cell transfusion within 7 days of delivery. Results In the total population the crude transfusion rates for women with planned caesarean delivery and intended vaginal delivery were 2.24 and 1.75%. After adjustment for maternal age, body mass index, birthweight, smoking, parity, number of infants and previous caesarean delivery, the risk of red blood cell transfusion was significantly lower in women with planned caesarean delivery compared with intended vaginal delivery (odds ratio 0.82; 95% CI 0.73-0.92; P < 0.01). In low-risk nulliparous women and in women with a previous caesarean delivery the transfusion rates were lower for planned caesarean delivery compared with intended vaginal delivery before and after adjustment. Conclusion Compared with intended vaginal delivery, planned caesarean delivery was associated with a reduced risk of severe postpartum haemorrhage indicated by use of red blood cell transfusion.