Plasma aldosterone levels in the 1st week of life in infants of less than 30 weeks gestation
ABSTRACT Plasma aldosterone levels were measured in 50 infants of less than 30 weeks gestation at 24 h (D1) and 7 days (D7). The relationship between the plasma aldosterone level and a number of clinical and biochemical variables was explored. Plasma aldosterone levels ranged from 1000 to 30000 pmol/l and were inversely correlated with the severity of illness (D1 or D7), serum sodium (D7) and 24 h sodium intake (D1). No correlation with the serum potassium level was noted. Conclusion:Plasma aldosterone levels in this extremely premature cohort were significantly greater than those reported in more mature infants. Important determinants were severity of illness and sodium homeostasis.
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ABSTRACT: Delay>24 h of age in neonates' first voiding attracts attention, although the phenomenon is usually benign. Earlier studies indicate that stress increases the infant's arginine vasopressin (AVP) and aldosterone secretion during birth. Our aim was to seek predictors of delayed first voiding and indirect evidence of AVP effect behind this phenomenon. The study population comprised 20 normal-term newborns whose first voiding was delayed>24 h of age (cases), and 19 age-matched control infants who voided for the first time at <24 h of age (controls). The first urine was collected and osmolality (U-Osm) and sodium content (U-Na) measured. The median of U-osm in cases was 432.50 (284-519) and in controls 337.50 (169-497) mOsm/L (p=0.005), and U-Na 21.50 (9-241) and 40.00 (13-226) mmol/L (p=0.001), respectively. Cases were more frequently born to primiparous mothers than controls (70% vs. 21%, p=0.004). Duration of labour was longer in cases than controls, first stage 10.5 h (3.92-20.50 h) versus 5.7 h (1.17-16.00 h) (p=0.045) and second stage 0.42 h (0.08-1.25 h) versus 0.17 h (0.08-0.92 h) (p=0.015). All seven (35%) abnormal cardiotocographies were recorded with cases (p=0.008). Delayed voiding appears to be related to a prolonged and stressful birth. Laboratory findings in the first urine suggest increased AVP and aldosterone secretion in such cases.Acta Paediatrica 07/2008; 97(7):904-8. DOI:10.1111/j.1651-2227.2008.00809.x · 1.84 Impact Factor
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ABSTRACT: Antenatal glucocorticoids are used to mature lung function in fetuses at risk for preterm delivery, but they also suppress cortisol synthesis in both pregnant women and their fetuses. We recently discovered in pregnant rabbits that even though exogenous betamethasone is not a mineralocorticoid, it also suppresses production of aldosterone. Lower aldosterone levels were linked to reduced P450 side chain cleavage (P450scc) messenger RNA levels in the rabbit maternal and fetal adrenal cortex. To establish whether this occurs in humans, we assayed aldosterone levels in women and newborns treated with antenatal betamethasone for preterm labor. In mothers treated with betamethasone, maternal cortisol depression after 48 hours was accompanied by aldosterone depression. Both pregnant women and their newborns treated with betamethasone showed depressed aldosterone levels in a 1- to 3-day period after the first betamethasone dose. We conclude that suppression of aldosterone biosynthesis is a side effect of antenatal steroids that has been largely overlooked, but may be clinically relevant at a time when the newborn is learning to control plasma electrolytes and blood volume.Reproductive sciences (Thousand Oaks, Calif.) 12/2008; 16(1). DOI:10.1177/1933719108324140 · 2.18 Impact Factor