Abstract
Introduction: Preterm delivery is a leading cause of neonatal morbidity and mortality, and early prediction remains a clinical priority. Fetal lymphoid organs such as the thymus and spleen may reflect intrauterine stress and immune development, offering potential as noninvasive markers.
Objectives: This study evaluated their diagnostic value in predicting delivery time.
Patients and Method: This cross‑sectional study was conducted at Imam Khomeini Hospital, Tehran, Iran, between August 2025 and February 2026. Using a simple randomized sampling method, 108 pregnant women with singleton gestations were enrolled at the time of delivery. Demographic and clinical data were collected through maternal interviews and review of medical records, while fetal thymus and spleen dimensions (length, width, and circumference) were measured immediately after birth by sonography performed by a gynecologist. Statistical analyses were conducted using SPSS version 27 to assess the association and diagnostic performance of fetal thymus and spleen size in predicting preterm delivery.
Results: Out of 108 pregnant women, 56 had term and 52 preterm deliveries. Fetal thymus size showed a significant inverse association with preterm delivery, with each 1‑mm increase in thymus length (adjusted odds ratio [OR] = 0.75, 95% CI: 0.62–0.91), width (adjusted OR = 0.77, 95% CI: 0.63–0.93), and circumference (adjusted OR = 0.87, 95% CI: 0.77–0.97) reducing the odds of preterm birth. In contrast, larger spleen dimensions were directly associated with higher risk, as reflected by adjusted ORs of 1.16 (95% CI: 1.04–1.28) for length, 1.19 (95% CI: 1.02–1.39) for width, and 1.17 (95% CI: 1.06–1.26) for circumference.
Conclusion: The findings suggest that a smaller thymus and a larger spleen appear to be associated with an increased likelihood of preterm birth occurring. Therefore, we concluded that fetal thymus and spleen measurements may serve as useful predictors of preterm delivery.