Risk factors for incomplete healing of the uterine incision after caesarean section

Abstract

To determine which factors increase the risk of large caesarean scar defects as assessed by transvaginal ultrasound. Observational cross-sectional study. University Hospital. One hundred and eight women who had undergone one caesarean section. Transvaginal ultrasound examination of the scar in the uterus 6-9 months after the caesarean. Published ultrasound definitions of large scar defects were used. Clinical information was obtained from medical records after all ultrasound images had been evaluated. Factors increasing the risk of large caesarean scar defects. Twenty-two (20%) women had a large caesarean scar defect. The odds of a large defect increased with cervical dilatation at caesarean (0 cm, 1-4 cm, 5-7 cm, 8 cm or more; odds ratio [OR] 4.4 [95% CI 0.7-28.5]; 26.5 [4.3-161.8]; and 32.4 [6.1-171.0]; P < 0.001), station of the presenting part at caesarean below pelvic inlet (OR 14.1 [4.6-43.1]; P < 0.001), duration of labour at caesarean (0 hour, 1-4 hours, 5-9 hours, 10 hours or more; OR 2.0 [0.2-23.8]; 13.0 [2.2-76.6]; and 33.1 [6.6-166.9]; P < 0.001), oxytocin augmentation (OR 6.3, [2.3-17.3]; P < 0.001), retroflexed uterus at ultrasound examination (OR 2.9 [1.0-8.3]; P = 0.047). According to multivariate logistic regression, no variable added information to cervical dilatation or the station of the presenting fetal part at caesarean. Caesarean in advanced labour is associated with increased risk of incomplete healing of the uterine incision as determined by transvaginal ultrasound.