Adrenocortical Steroids in Small-for-Gestational-Age Term Infants during the Early Neonatal Period1,2

Abstract

ABSTRACT. We evaluated adrenocortical steroid concentrations a t birth and during postnatal adaptation (2 h until 7 days) in 10 vaginally delivered term small-for-gestational-age (SGA) infants and 1 2 term appropriate-forgestational age infants. Plasma aldosterone, ll-deoxycorticosterone, corticosterone, progesterone, 17-hydroxyprogesterone, 11-deoxycortisol, cortisol, and cortisone were longitudinally measured by specific RIA after Sephadex LH-20 chromatography. Mean aldosterone was significantly higher in SGA than in appropriate-for-gestationalage infants (2 h to 7 days; p < 0.001). In SGA infants, cortisone and cortisol levels were significantly lower in umbilical artery (p < 0.05), and all glucocorticoid levels were significantly lower 12 h after birth (p < 0.05). Thereafter (24 h to 7 days), only 11-deoxycortisol levels remained significantly lower in SGA; corticosterone and cortisol levels were even higher @ < 0.05) in SGA 24 h after birth. The data suggest that SGA infants maintain high aldosterone levels throughout the 1st wk of life. Low cortisol and cortisone levels in umbilical artery a s well a s low glucocorticoid levels a t 2 h and/or 1 2 h compared to term appropriate-for-gestational-age infants may reflect either a less stressful postnatal adaptation or, more likely, a reduced adrenocortical synthesis in term SGA infants. (Pediatr Res 25:115-118, 1989) Abbreviations SGA, small for gestational age UA, umbilical artery AGA, appropriate for gestational age Perinatal problems in neonates with severe intrauterine growth retardation are frequent. They include asphyxia, a high neonatal mortality, electrolyte imbalance, hypoglycemia, cardiorespiratory problems, and neurologic abnormalities (1). Organ weights are significantly reduced (2); in particular, the adrenal cortex is small with respect to size and cell number (3).

Reference range for serum cortisol in well preterm infants

“…The concentrations of several glucocorticoids, including cortisol, were lower in term SGA infants than in AGA infants at 12 hours of age, but the cortisol values at 24 hours of age were higher, and after the first day of life no differences were found in cortisol values between term SGA and AGA infants 25. These findings suggest a different adrenocortical response in SGA infants and we therefore separated out the SGA infants before further analysis.…”

Plasma aldosterone levels in the 1st week of life in infants of less than 30 weeks gestation

“…This system has an important role in the maintenance of blood pressure and homeostasis of serum sodium and potassium. The RAAS is known to be active from at least 16 weeks of fetal life [15] with relative aldosterone resistance diminishing throughout the 1st year of life [2,3,4,5,6,7,10,14,16,19,20,21,22]. The most preterm infants reported to date have had gestations between 30 and 32 weeks [22], where the plasma aldosterone level in the first 6 weeks of life ranged from 5700 to 18000 pmol/l (ng/dl · 27.75 = pmol/l).…”

Serum Concentrations of Adrenal Steroids and Their Precursors as a Measure of Maturity of Adrenocortical Function in Very Premature Newborns

“…On the other hand, the high steroid precursor levels in preterm infants may have cross-reacted in some previous studies using direct steroid assays without prior extraction and purification. In those reports having used the same steroid separation and assays as this study [23,24,25,26], the S/F ratio in fairly unstressed term or moderately preterm infants was 5- to 10-fold compared to the stressed preterm infants in our study. In one of the previous studies [16], ACTH stimulation decreased the S/F ratio down to about 50% of the mean basal value, when the F level increased.…”