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

Abstract

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 signifi cant 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 signifi cant 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 specifi city 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.

Adrenal volumes in fetuses delivering prior to 32 weeks' gestation: An MRI pilot study

“…While three studies have previously demonstrated either whole gland or fetal zone enlargement, the use of clinically unavailable techniques, or need for highly experienced sonographers, are likely to have hindered clinical translatability. 10,23,24 To our knowledge, two previous studies have attempted to assess the normal fetal adrenal gland on MRI: one used single coronal images to determine a length and thickness to the gland 11 there was no consistency in slice used and it is unclear which measurements of the adrenal are most affected by volumetric change rendering this less relevant. Assessment of whole volumes is likely be more applicable to clincial practice.…”

“…Nonetheless, ultrasound assessment of the fetal adrenal for the prediction of preterm birth in high risk patients has been attempted. While three studies have previously demonstrated either whole gland or fetal zone enlargement, the use of clinically unavailable techniques, or need for highly experienced sonographers, are likely to have hindered clinical translatability 10,23,24 …”

“…While three studies have previously demonstrated either whole gland or fetal zone enlargement, the use of clinically unavailable techniques, or need for highly experienced sonographers, are likely to have hindered clinical translatability. 10 , 23 , 24 …”

“…While ultrasound assessment of the adrenals has been investigated as a biomarker of both placental insufficiency 8 and preterm birth, 9,10 this has never been integrated into clinical practice, perhaps because of difficulty replicating results in a small and irregularly shaped organ and heterogeneity of populations investigated.…”

“…While ultrasound assessment of the adrenals has been investigated as a biomarker of both placental insufficiency 8 and preterm birth, 9,10 this has never been integrated into clinical practice, perhaps because of difficulty replicating results in a small and irregularly shaped organ and heterogeneity of populations investigated. Normal length and thickness of adrenal glands in healthy fetuses has been derived from fetal magnetic resonance imaging (MRI), 11 but volumetric ranges have been suggested based on post‐mortem cases only 12 …”