Urinary Steroid Levels in Newborn Infants with Intra-uterine Growth Retardation

Abstract

Urinary steroid excretion of 6β-OH-cortisol (6β-OH-F), tetrahydrocortisone (THE), l6α-OH-pregnenolone (16α-0H-PG) and 16a-OH-dehydroepiandrosterone (16α-OH-DHA) was determined in 23 full-term normal newborn infants, 8 normally grown premature and 8 intra-uterine growth retarded (IUGR) newborns. The method used measured free, glucuronide- and sulfate-conjugated steroids. Labeled internal standards were used for each steroid measured. The excretions were expressed in relation to urinary creatinine levels. Steroid excretion values in the normally grown full-term and premature groups were quite similar. On comparison of steroid excretion values in the IUGR and normal full-term groups by the Mann-Whitney (two-tailed) test, there were no significant differences in 6β-OH-F and THE excretions but the excretions of 16α-0H-PG and 16α-0H-DHA were significantly less (p < 0.02 and p < 0.01, respectively) in the IUGR group. The ratio 6β-OH-F + THE/16α-OH-PG + 16α-OH-DHA was significantly greater in the IUGR infants than in the normal full-term newborns (p < 0.001). The results indicate no evidence of cortisol deficiency in IUGR infants. The low 16α-0H-DHA excretions fit with the frequent finding of low estriol excretions by women bearing IUGR fetuses. The cause of the dichotomy between cortisol and Δ5-3β-hydroxysteroid secretion by the IUGR neonatal adrenal is unknown.