(184) Association between Indication for Previous Cesarean Delivery and the risk for Uterine Rupture in TOLAC

Objective:
To determine whether the indication for previous cesarean delivery (CD) is associated with the risk of uterine rupture in women undergoing trial of labor after cesarean (TOLAC).

Study Design:
A retrospective cohort study was conducted at a single university-affiliated tertiary center. The study included all women with one previous CD who attempted a TOLAC at our institution between 2012-2024, regardless of whether the trial ended in vaginal birth or intrapartum CD. Among all women who underwent TOLAC after one prior CD, only those with a clearly documented indication for the prior CD were eligible for inclusion. Women with a nonviable fetus or contraindications to TOLAC were excluded.

Indications for previous CD were categorized into four groups:

1.     Antepartum indications –mal-presentation, maternal request and others non- labor indications

2.     Suspected Fetal distress –non-reassuring fetal heart rate, cord prolapse, reduced fetal movements

3.     First-stage dystocia – dysfunctional labor, failed induction

4.     Second stage dystocia –arrest of descent, failed vacuum

Risk factors were assessed using multivariable logistic regression analysis.

Results:
1. During the study period, 147,045 women delivered at our center. Of these, 1,806 women met inclusion criteria; 91 women (1.6%) were diagnosed with uterine rupture.

2. Prior CD due to second-stage dystocia was significantly more common in the rupture group (12.1% vs. 3.2%, p< 0.001)

3. In multivariate analysis, second-stage dystocia was an independent predictor for uterine rupture (OR 3.9, 95% CI 1.14–13.37, p=0.03)

4. No other indications were significantly associated with uterine rupture. First-stage dystocia was excluded from multivariable analysis due to limited number of events (n=4). Time interval between prior CD and TOLAC did not differ significantly between groups (2.7 vs. 2.6 years, p=0.31)

Conclusion:
Second-stage dystocia as an indication for previous CD was independently associated with a nearly fourfold increased risk of uterine rupture during TOLAC. This indication-specific risk warrants explicit consideration in delivery planning and counseling