Objective: To determine whether the method used to expand the uterine incision for caesarean delivery affects the incidence of intra-operative haemorrhage.
Design: A prospective randomised study of women undergoing a low segment transverse caesarean delivery. Participants were assigned to have their uterine incision either sharply or bluntly expanded.
Participants: Between June 1998 and June 2000, 470 women drew assignments to the sharp expansion group and 475 to the blunt group.
Results: The maternal demographics of age, race, nulliparity, and body mass index as well as pre-operative haematocrit were similar between groups. Compared with the blunt group, the estimated blood loss (886 versus 843mL, P = 0.001), change in the mean haematocrit (6.1% versus 5.5%, P = 0.003), incidence of postpartum haemorrhage (13% versus 9%; relative risk = 1.23, 95% CI 1.03, 1.46) and need for a transfusion (2% versus 0.4%; relative risk = 1.65, 95% CI 1.25, 2.21) were significantly greater in the sharp group.
Conclusion: In caesarean delivery, sharply expanding the uterine incision significantly increases intra-operative blood loss and the need for subsequent transfusion.