Ultrasonographic Evaluation of Adrenal Involution during Antenatal and Neonatal Periods

Abstract

Using real-time ultrasonography, 25 adrenal glands from prenatal to neonatal periods were prospectively examined to assess the process of shrinkage. A similar sonographic structure was seen in both prenatal and neonatal adrenal glands. The area of adrenal gland (AGA) and the rate of decrease were calculated during antenatal and early neonatal periods. The values of AGA were 350 ± 19 mm2 within a week of delivery, 304 ± 17 mm² (87 ± 2%) just after delivery, 273 ± 25 mm² (77 ± 5%) on the 1st day, 246 ± 24 mm² (70 ± 5%) on the 2nd day, 215 ± 23 mm² (61 ± 5%) on the 3rd day, 196 ± 22 mm² (56 ± 5%) on the 4th day, 173 ± 18 mm² (50 ± 4%) on the 5th day, 154 ± 14 (44 ± 4%) on the 6th day, 140 ± 12 mm² (40 ± 2 %) on the 7th day, respectively. In conclusion, the postnatal involution of the adrenals was documented by ultrasound.

The Androgen Metabolome of Preterm Infants Reflects Fetal Adrenal Gland Involution

“…Moreover, the same pattern has also been described for plasma and urinary DHEA-S levels in preterm and full-term infants (28,29); and in the same line higher DHEA-S levels were reported for extremely preterm infants (23-26 weeks gestation) compared to very preterms (27-29 weeks gestation) in the first week of life (30). Morphometric studies using prenatal and neonatal ultrasound imaging or autopsy methods revealed that the fetal adrenals shrink faster in full-term compared to preterm infants (31,32). On the other hand, a study including infants of 26-35 weeks gestation suggested that parturition is the trigger for the involution of the fetal adrenals (33).…”

Parturition Itself Is the Basis for Fetal Adrenal Involution

“…A decline in steroid secretion at birth is also well documented (1, 8 -11). It was suggested that in full-term infants the adrenal gland involutes more rapidly (13,14). Results of this study show that within the first 2 wk of life, the large fetal adrenal shrinks to its normal infantile size.…”