Can three-dimensional ultrasound measurement of fetal adrenal gland enlargement predict preterm birth?

Purpose: To assess the diagnostic accuracy of three-dimensional (3D) ultrasound measurements of fetal adrenal gland volume (AGV) and fetal zone enlargement (FZE) as predictors of PTB compared to measurements of cervical length (CL) and cervicovaginal fetal fibronectin (CVFF).

Method: This prospective study included women presenting at 28-36 weeks of gestation with threatened preterm labor (TPL). Fetal AGV and FZE were measured using 3D ultrasound. Two-dimensional (2D) ultrasound was used to measure the CL. The AGV was corrected for the ultrasound-estimated fetal weight (cAGV). Qualitative CVFF detection was also performed. The diagnostic accuracy of cAGV, FZE, CL, and CVFF was compared considering preterm birth (PTB) within 7 days of recruitment as the main outcome measure.

Results: Seventy-five pregnant women were included in the final statistical analysis. Twenty-seven women (36 %) delivered within 7 days. cAGV and FZE had the highest sensitivities and specificities to predict PTB within 7 days when compared with CL and CVFF. Multivariate analysis, including cAGV, FZE, CL, and CVFF, revealed that cAGV and FZE were independent predictors of PTB within 7 days in the study participants.

Conclusion: In women who presented at 28-36 weeks of gestation with TPL, cAGV and FZE can be used as independent predictors of PTB.