NEW ORLEANS – Vertical incisions in morbidly obese women undergoing a primary cesarean delivery are associated with fewer wound complications, compared with transverse incisions.
The findings were "contrary to expectations," presenter Dr. Caroline C. Marrs told an audience at the annual Pregnancy Meeting sponsored by the Society for Maternal-Fetal Medicine.
Dr. Carolyn Marrs
The registry study of morbidly obese women who had had a primary C-section showed that those with a vertical incision were found to have higher rates of all adverse maternal outcomes, except for transfusions, but had lower incision-to-delivery times (9.2 plus or minus 5.5 vs. 11.1 plus or minus 6.1, P less than .001). "However, there was significant confounder bias, because after adjusting for significant baseline and clinical characteristics such as race, smoking status, and body mass index, vertical incisions were not associated with higher rates of composite maternal morbidity," said Dr. Marrs of the University of Texas Health Science Center in Houston.
Using data collected between 1999 and 2002 for the cesarean registry of the Eunice Kennedy Shriver National Institute of Child Health and Human Development Maternal-Fetal Medicine Units Network from 19 academic medical centers, Dr. Marrs and her colleagues identified 3,200 women with a body mass index of 40 kg/m2 at the time of their delivery by primary C-section whose incision type was known
The transverse skin incision cohort numbered 2,603 (81%), and the vertical incision group was 597 (19%).
An analysis of patient characteristics indicated the type of incision a woman had positively correlated with her race, smoking status, and insurance type, as well as whether the woman had gestational diabetes, chorioamnionitis, non–lower-segment hysterotomy, and an emergency C-section.
Logistical regression showed that vertical skin incisions were associated with parity (1.16, adjusted odds ratio 1.09-1.25); black race (1.24, AOR 1.03-1.51), maternal body mass index (1.06, AOR 1.04-1.08), low transverse hysterotomy (4.46, AOR 3.21-6.20), and nonemergent cesarean delivery (0.49, AOR 0.39-0.62).
A univariate analysis of composite wound complications such as seroma or hematoma indicated that vertical wounds were more associated with higher complication rates (4.2% of the vertical group vs. 1.7% of the transverse group, P less than .001).
Multivariate progression analysis indicated that the adjusted odds ratio for a vertical incision being a risk factor for wound complications was 0.32 (0.17-62). Other risk factors noted were: nonwhite race (0.48, AOR 0.25 to 0.94), maternal BMI (1.05, AOR 1.00 to 1.09), and ASA score (2.10, AOR 1.21-3.65).
"We suspect selection bias played a role," said Dr. Marrs. "Given the differences in baseline clinical characteristics of women who had vertical incisions, surgeons may have chosen this route based on selected factors such as BMI or need for emergency delivery."
Dr. Marrs did not have any relevant disclosures.