(1001) Clinical outcomes following unintended hysterotomy extension during second-stage labor cesarean

Objective:
Unintended hysterotomy extensions are common in second-stage cesarean delivery and may cause tissue trauma with implications for future pregnancies, including risk of spontaneous preterm birth (sPTB). We evaluated subsequent pregnancy outcomes after unintended hysterotomy extension during second-stage cesarean delivery.

Study Design:
Retrospective cohort study of patients who underwent second-stage cesarean between March 2014–August 2024 and had a subsequent delivery ≥14 weeks at an academic tertiary care center. Unintended extension was defined as a documented extension beyond the initial hysterotomy; planned T or J incisions were excluded. The primary outcome was the occurrence of sPTB in the subsequent pregnancy. Secondary outcomes included delivery outcomes of the index and subsequent pregnancies. Multivariate logistic regression was performed on subsequent pregnancy outcomes to model the effect of hysterotomy extension.

Results:
A total of 268 patients met inclusion criteria, with 70 (25.4%) having a documented unintended hysterotomy extension during second-stage cesarean delivery. Of those with extensions, 10/70 (14.3%) involved the cervix. In unadjusted analysis, rates of subsequent sPTB were similar in the unintended extension group compared to the no-extension group (11.4% vs. 5.6%, p=0.100). However, in a multivariate logistic regression controlling for confounders, patients with an extension in their index cesarean delivery had significantly higher odds of sPTB in their subsequent pregnancy (aOR 2.83, 95% CI 1.03–7.8). Compared to no extensions, patients with extensions had significantly greater operative estimated blood loss, longer operative times, and higher rates of postpartum hemorrhage, O’Leary stitch placement, interventional radiology embolization, blood transfusion, and maternal ICU admission (all p < .05, Table 1).

Conclusion:
Hysterotomy extensions significantly increased maternal morbidity in the index pregnancy and increased the odds of sPTB in the subsequent pregnancy. Future studies should assess methods for primary prevention of hysterotomy extensions.