(202) Predicting Periviable Delivery: Identifying Risk Factors Among Patients Admitted Between 21-24 Weeks

To identify factors associated with delivery < 25 weeks in patients with periviable admissions.

Study Design:

We conducted a retrospective cohort study of patients admitted between 21w0d-24w6d at a single tertiary care center from 2018-2024. Patients were stratified by gestational age at delivery (< 25 vs ≥ 25 weeks). Maternal demographics, admission characteristics, counseling, interventions, and outcomes were compared using appropriate statistical tests. A Kaplan-Meier analysis was used to estimate gestational age at delivery.

Results:

Among 255 patients included with periviable admissions, 72 (28.2%) delivered < 25 weeks. Significant predictors of delivery < 25 vs ≥25 weeks included higher BMI (32.1 vs 29.7, p=0.019), Black race (32.6% vs 10.0%, p=0.003), multiple gestations (16.7% vs 5.5%, p=0.011), and admission for spontaneous preterm labor (45.8% vs 11.5%, p< 0.001) or PPROM (43.1% vs 13.7%, p< 0.001). There were no significant differences in maternal age or ethnicity. Kaplan-Meier survival analysis showed 50% of the patients who received periviability counseling delivered before 27 weeks versus 37 weeks for the group without counseling.

Antenatal interventions such as corticosteroids, magnesium sulfate, and tocolysis were similarly planned for patients who ultimately delivered < 25 vs ≥ 25 weeks, with no significant differences.

Conclusion:

These findings may inform prospective identification strategies to guide early counseling and targeted periviable management. The differences in delivery timing between the counseled (50% by 27 weeks) and non-counseled (50% by 37 weeks) groups suggest clinicians are already identifying high-risk cases, though future predictive tools could enhance risk stratification at the time of admission.