Current Evidence Favors Blunt Hysterotomy for Cesarean Deliveries

In lower-segment cesarean deliveries, blunt dissection of the uterine incision is associated with less blood loss than sharp dissection, according to the findings of a recent systematic review and meta-analysis.¹
   
There are several techniques that help minimize intraoperative blood loss related to an obstetric hemorrhage during cesarean delivery-a complication that is a leading cause of maternal morbidity and death. One such technique is using fingers instead of scissors to expand the incision, or blunt dissection. According to the authors, the benefits of blunt dissection are decreased trauma to blood vessels, faster delivery of the baby, and reduced risk of injury to the umbilical cord and neonate. The authors also cite potential disadvantages of this approach, which are reduced control over the uterine incision, possible vascular damage causing hemorrhage, and risk of postsurgical endometritis.

To compare the effects of blunt dissection with sharp dissection, the authors indentified 4 randomized controlled trials involving 1731 patients that were suitable for their analysis. Overall, blunt expansion of the uterine incision was associated with a trend toward less maternal blood loss. This trend was statistically significant when measured by the surgeon’s estimation of blood volume lost but did not reach significance when preoperative and postoperative hematocrit and hemoglobin levels were compared.

Three of the 4 included studies evaluated maternal blood loss by measuring hematocrit levels before and after surgery. When these 3 studies were analyzed, there was a trend toward less blood loss in the blunt dissection group compared with the sharp dissection group, but the difference did not reach statistical significance. When preoperative and postoperative hemoglobin levels were compared, which also occurred in 3 studies, the results showed a trend toward less blood loss in the blunt dissection group as well, but they were not statistically significant. In addition, blood transfusions and unintended extension of the uterine incision occurred less often with blunt dissection than with sharp dissection, but statistical significance was not reached for either trend. Operative time and the incidence of postoperative endometritis did not differ between study groups.

The authors concluded that the available evidence shows that blunt dissection is associated with less maternal blood loss than sharp dissection. However, they note that a large unpublished trial comparing these techniques was recently completed, and the unreported data could alter these findings.

Pertinent Points:
- Blunt dissection, compared with sharp dissection, is associated with trends toward less blood loss, less need for blood transfusions, and fewer incidences of unintended extension of the uterine incision.
- The results of a new but yet unpublished large study may alter these conclusions.

References:

1. Xu LL, Chau AMT, Zuschmann A. Blunt vs sharp uterine expansion at lower segment cesarean section delivery: a systematic review with meta-analysis. Am J Obstet Gynecol. 2013;208:62.e1-8.