Pfannenstiel versus Vertical Skin Incision for Cesarean Delivery in Women with Class III Obesity: A Randomized Trial.

Objective: To compare Pfannenstiel versus vertical skin incision for the prevention of cesarean wound complications in morbidly obese women.

Study Design: Women with body mass index ≥ 40 kg/m undergoing cesarean delivery (CD) were randomly allocated to Pfannenstiel or vertical skin incision. The primary outcome was a wound complication within 6 weeks. Due to a low consent rate, we limited enrollment to a defined time period for feasibility. We conducted a traditional frequentist analysis with log-binomial regression to obtain relative risks (RRs), and a Bayesian analysis to estimate the probability of treatment benefit. A priori, we decided that a ≥60% probability of treatment benefit for either incision type would be convincing evidence to pursue a larger trial.

Results: A total of 648 women were approached, 228 were consented, and 91 were randomized. The primary outcome rate was 19% in the Pfannenstiel group and 21% in the vertical group (RR: 1.18; 95% confidence interval: 0.49-2.85). Bayesian analysis revealed a 59% probability that Pfannenstiel had a lower primary outcome rate.

Conclusion: In the first published randomized trial to compare skin incision types for obese women undergoing CD, we were unable to demonstrate differences in clinical outcomes. Our trial suggests that a larger study would have a low probability for different findings.

Trial Registration: NCT 01897376 (www.clinicaltrials.gov).