Ultrasound Measurement of the Fetal Adrenal Gland and Prediction of Preterm Birth

Introduction Identifying a marker that is highly sensitive, specific, noninvasive, and cost-effective for predicting preterm labor remains a critical clinical priority. We propose that ultrasound assessment of fetal adrenal gland morphometry, especially measurement of adrenal gland volume, may help discriminate pregnancies at higher short-term risk of delivery among women presenting with threatened preterm labor. Objective The objective of the study is to evaluate the short-term discriminative performance of ultrasound-derived fetal adrenal gland morphometric parameters, particularly the fetal zone depth-to-total gland depth (d/D) ratio and corrected adrenal gland volume (cAGV), in identifying the risk of delivery within seven days in patients with threatened preterm labor. Methods This retrospective study included 52 singleton pregnancies between 28 and 35 weeks' gestation. Fetal adrenal gland dimensions and the fetal zone were measured via transabdominal ultrasound. Logistic regression and receiver operating characteristic (ROC) analysis were used to assess predictors of preterm birth within seven days of ultrasound evaluation. Results Both d/D ratio and cAGV were significantly higher in the early delivery group (p < 0.0001). Multivariable logistic regression identified d/D ratio as the strongest association with delivery within seven days. The model yielded an area under the curve (AUC) of 0.88. At the optimal probability threshold of 0.59, sensitivity was 85.7%, specificity 79.2%, positive predictive value (PPV) 82.8%, and negative predictive value (NPV) 83.3%. Conclusion Fetal adrenal morphometry, particularly d/D ratio and cAGV, can serve as valuable predictors of imminent preterm delivery and should be integrated into clinical assessment tools for symptomatic patients.