Body mass index and operative times at cesarean delivery.

OBJECTIVE: To examine the relationship between body mass index (BMI, kg/m) and incision-to-delivery interval and total operative time at cesarean delivery.
METHODS: Women with singleton gestations undergoing uncomplicated primary and repeat cesarean deliveries were identified from the Maternal-Fetal Medicine Units Network Cesarean Registry. Women were classified by BMI category at time of delivery (normal 18.5-24.9, overweight 25.0-29.9, obese 30.0-39.9, and morbidly obese 40 or greater). Incision-to-delivery interval and total operative times during cesarean delivery were compared among the three groups. Primary outcome was prolonged incision-to-delivery interval as defined by 90th percentile or greater of the study population or 18 minutes or longer.
RESULTS: Of the 21,372 women included in the analysis, 9,928 were obese (46.5%) and 2,988 (14.0%) were morbidly obese. Longer operative times were found among women with overweight (median [interquartile range] incision-to-delivery: 9.0 [6.0] and total operative time: 45.0 [21.0] minutes), obese (10.0 [7.0]; 48.0 [22.0] minutes), and morbidly obese BMIs (12.0 [8.0]; 55.0 [26.0] minutes) compared with women with normal BMI at delivery (9.0 [5.0]; 43.0 [20.0] minutes) (P<.001). Morbidly obese women had a more frequent incision-to-delivery interval that was 18 minutes or longer (n=602 [20%] compared with 127 [6%] in normal BMI). After adjustments including number of prior cesarean deliveries, incision-to-delivery interval 18 minutes or longer was significantly related to obese (odds ratio [OR] 1.62, 95% confidence interval [CI] 1.31-2.03) and morbidly obese (OR 2.81, 95% CI 2.24-3.56) BMI at delivery.
CONCLUSION: Increasing BMI is related to increased incision-to-delivery interval and total operative time at cesarean delivery with morbidly obese BMI exposing women to the highest risk of prolonged incision-to-delivery interval. LEVEL OF EVIDENCE: : II.