Simple ultrasound evaluation of fetal adrenal glands as a marker of imminent preterm birth: a preliminary report.

OBJECTIVE

We present a simple 2D big ultrasound measurement of the fetal adrenal glands and their biometrical growth analysis highlighted as a potential preterm birth marker.

METHODS

This was a prospective observational case-control study. Sixty-four patients were included in the study (32 with the diagnosis of imminent preterm birth before 37 and 32 controls) from January 2018 to May 2020. Anteroposterior dimensions and circumferences of the whole adrenal glands and their central zones were measured by simple B-mode ultrasound imaging. For the statistical analysis, StatsDirect 3.0 and ROC curves were used. As a studied descriptor, routine standard ultrasound cervical measurements were added (cervical length, funneling, sludge, cervical dilatation, and cervical glandular area).

RESULTS

In biometrics of gestational age-related changes, a significant analysis of the overall growth of the adrenal gland was observed (circumference p < 0.001, anteroposterior diameter p = 0.02). The growth of the central zone was observed independently of gestational age. The growth of the central zone of the fetal adrenal glands revealed significant changes between the group of patients who delivered prematurely and control groups (p < 0.01). The ideal cut-off value of the proportion of enlargement of the fetal zone as a predictor of preterm delivery before week 37 was 45.1 %, with the sensitivity of 87.5 % and specificity of 85.4 %.

CONCLUSIONS

A simple 2D B-mode measurement of the fetal adrenal glands´ central zone growth can be applied as an additional marker in the prediction of true preterm delivery. The natural biometrical overall growth of the adrenal glands seems to be dependent on gestational age, whereas that of the central adrenal gland zone seems to be independent on gestational age (Tab. 3, Fig. 5, Ref. 26).