Cohen vs Pfannenstiel cesarean skin incision for body mass index ≥35 kg/m2: a randomized controlled trial

Abstract

Background: Maternal obesity is recognized as a significant risk factor for adverse pregnancy outcomes, including increased cesarean delivery rates and heightened surgical complications. It is unclear if the Cohen or Pfannenstiel skin incisions at cesarean delivery are associated with different outcomes. Objective: To evaluate the impact of either Cohen or Pfannenstiel cesarean skin incision type on maternal morbidity. Study Design: Pregnant individuals with a BMI of ≥35 kg/m2, carrying either singleton or multiple gestations, were consented prenatally and in labor. Eligible participants who underwent a cesarean delivery between 24 and 41 weeks of gestation were randomized to either Pfannenstiel or Cohen skin incisions at Thomas Jefferson University Hospital from October 2016 to March 2020. The study aimed to recruit 284 participants based on a sample size calculation assuming a 50% reduction in wound complications with Cohen versus Pfannenstiel incisions (80% power, α=0.05), but recruitment was terminated early after 72 participants were randomized. The primary outcome was a composite maternal morbidity within six weeks, which consisted of the following: wound infection, hematoma, seroma, separation of skin ≥1 cm, readmission for wound complications, endometritis, and postpartum hemorrhage. Statistical analyses included bivariate tests, t-tests, and non-parametric analyses. Results: Of 331 pregnant individuals consented prenatally and in labor, 72 eventually underwent cesarean delivery and were randomized, 34 to Cohen and 38 to Pfannenstiel skin incisions. The mean BMI was >42 kg/m2, about two thirds of the patients had a pannus, 56% were Black, 47% had diabetes, and 56% hypertensive disorders. The primary outcome of composite maternal morbidity occurred in 47.1% in the Cohen and 36.8% in the Pfannenstiel groups (RR 1.24, 95% CI 0.71-2.08), and was also similar regardless of the presence of a pannus, or by degree of obesity. Surgical site infection, hematoma, seroma, wound separation/dehiscence, endometritis, and postpartum hemorrhage were each similar between Cohen and Pfannenstiel participants. Neonatal outcomes were also similar between the Cohen and Pfannenstiel groups, except that the Cohen group was found to have statistically significant lower Apgar score at 5 minutes and higher need for respiratory support compared to the Pfannenstiel group, possibly related to the trend for a longer time from skin incision to delivery. Physicians were found to be significantly less satisfied with the Cohen compared to the Pfannenstiel incision. Conclusion: In pregnant patients with BMI of ≥35 kg/m2, obstetrical providers can chose from either a Cohen or an Pfannenstiel skin incision, as they are associated in general with similar outcomes, except for lower Apgar scores and lower physician satisfaction associated with the Cohen incision. The findings of this study are limited by its early cessation for logistical reasons, leading to an underpowered analysis. It is crucial to acknowledge that these results must be interpreted cautiously due to the reduced sample size and the circumstances surrounding the study's termination. These data can inform future trial design and implementation as well as fuel individual patient level meta-analyses on this topic.