(1112) Prediction Model for Intrapartum Cesarean Delivery among Women with Clinical Chorioamnionitis

Although prior studies have identified risk factors for cesarean delivery (CD) in women with clinical chorioamnionitis, no predictive model has been developed. Hence, we aimed to identify risk factors and construct a model for intrapartum CD in this population.

Study Design:

A retrospective cohort study was conducted at a university-affiliated tertiary center (2013–2024). The study included all singleton pregnancies ≥37 weeks undergoing a trial of labor and diagnosed with clinical chorioamnionitis, defined as intrapartum fever ≥38°C with administration of broad-spectrum antibiotics. Exclusions: prior CD, multiple gestation, non-viable fetuses, or CD without labor. Vaginal deliveries were compared to intrapartum CDs. Multivariable logistic regression identified predictors; model performance was evaluated using receiver operating characteristic (ROC) analysis.

Results:

1. Among 119,034 deliveries during the study period, 2,296 (1.9%) were diagnosed with clinical chorioamnionitis; of these, 272 (13.4%) underwent intrapartum CD.


2. Positive cultures: 8.8% in CD group vs. 8.7% in vaginal group (p=0.966).


3. Risk factors for CD included: oxytocin use (OR 2.64, 95% CI 1.33–5.22), hemoglobin < 10.5 g/dL (OR 2.07, 95% CI 1.23–3.48), nulliparity (OR 2.00, 95% CI 1.12–3.58), body mass index ≥25kg/m² (OR 1.82, 95% CI 1.32–2.50), gestational age  ≥40 weeks (OR 1.81, 95% CI 1.31–2.50), age >35 years (OR 1.72, 95% CI 1.23–2.42), white blood cell count >16,000/µL (OR 1.53, 95% CI 1.13–2.07), meconium-stained fluid (OR 1.45, 95% CI 1.06–1.98), gestational weight gain >15 kg (OR 1.37, 95% CI 1.02–1.85).


4. Epidural anesthesia was associated with a lower risk for CD (OR 0.21, 95% CI 0.14–0.31).


5. Main CD indications: arrest/cephalopelvic disproportion (44.1%), non-reassuring fetal heart rate (40.8%).


6. Model performance: AUC 0.742 (95% CI 0.709–0.775; p< 0.001). Cutoff score of 10: 74% sensitivity, 63% specificity.

In clinical chorioamnionitis, several maternal and labor factors predicted intrapartum CD. This model supports risk stratification and may improve decision-making.