Risk Factors and Maternal Morbidity Associated with Unintentional Hysterotomy Extension at the Time of Cesarean Delivery

Objective Our aim was to estimate the incidence of unintentional hysterotomy extension at the time of cesarean delivery and to identify associated risk factors and maternal morbidity. Study Design We conducted a secondary analysis of a randomized controlled trial evaluating chlorhexidine-alcohol versus iodine-alcohol for skin antisepsis in women undergoing cesarean delivery. We included patients with a low transverse hysterotomy. The primary outcome was the incidence of unintentional hysterotomy extension. Logistic regression was performed to identify independent factors associated with hysterotomy extension. Maternal morbidity was compared between patients with and without extension. Results Of 1,038 patients meeting the inclusion criteria, 71 (6.8%; 95% confidence interval [CI]: 5.4-8.5%) experienced a hysterotomy extension. Of several potential risk factors assessed, the second stage of labor was the only independent predictor of hysterotomy extension (adjusted odds ratio: 10.2; 95% CI: 2.6-39.8). Hysterotomy extension was associated with increased operative time (73 vs. 55.3 minutes; p < 0.01), need for blood transfusion (relative risk: 5; 95% CI: 1.6-15.2), and rate of additional surgical injury (RR: 17; 95% CI: 6.9-41.8). Conclusion Hysterotomy extensions are not infrequent at the time of cesarean delivery and are associated with increased maternal morbidity. Cesarean delivery during the second stage of labor is the main independent risk factor for hysterotomy extension.