Significance of accidental extensions in the lower uterine segment during cesarean delivery.

Objectives: This study was undertaken to determine risk factors and perioperative complications associated with accidental extensions in the lower uterine segment during cesarean deliveries (CDs).

Study Design: This is a retrospective chart review of all CDs performed at Jackson Memorial Hospital/University of Miami between the years 1999 and 2002. Operative reports were reviewed to abstract data on the occurrence of extensions. Indication for CD, cervical status at the time of CD, birth weight, and fetal presentation and position were included in the analyses. Postoperative hematocrits, length of surgery, estimated blood loss, decline in hematocrit by 10%, need for transfusion, or hysterectomy were compared among CD with and without extensions.

Results: A total of 2,811 CDs were available for this study. Accidental extensions in the lower uterine segment occurred in 6.6% of the cases. Extensions were more commonly found in primary CD (8% vs 5%, P < .01. Extensions were more frequent if cervical dilatation was 8 cm or greater (18.3% vs 7%, P < .01), complete effacement (15% vs 8%, P < .01) station greater than +1 (16% vs 6.9%, P < .01), and if the fetal position was noted to be in the occiput posterior position (10% vs 5%, P < .01). When extensions were present, length of surgery was longer (56 vs 49 minutes, P < .01) and estimated blood loss was greater (994 +/- 675 mL vs 936 +/- 370 mL, P < .01). Arrest of descent as indication for CD was found to be an independent risk factor for the occurrence of extensions during CD (odds ratio 2.6, 95% CI 1.5-4.5, P = .001).

Conclusion: Extensions in the lower uterine segment during CD do not increase maternal morbidity.