Alteration in the thyroid metabolism of hypoxic, fasted, and chronically ill adults and older children have been described. Present study was carried out to evaluate the effects of hypoxia on thyroidal in-dices of term newborns and compared them to those of a control population. Blood was drown from the cord and then serially at 3, 24, and 48 hours after delivery in all patients. Twenty healthy term newborns (group I) increased their free thyroxine (FT4) concentrations significantly after delivery from a mean SD baseline of 0.94 0.13 ng/dl in cord blood to a mean SD of 2.6 0.5 ng/dl, 48 h after delivery (p < 0.001), while their free triiodothyronine (FT3) levels increased from a mean f SD baseline level of 2.3 f 0.5 pg/ml in cord blood to a mean f SD peak of 3.7 f 0.5 pg/ml 48 hours after delivery (p < 0.001).
Twentyone term newborns with transient low Apgar scores at birth (group lI) and sixteen term neonates born to mothers with toxemia or hypertension (group 111) tailed to increase their FT4 and FT3 concentrations above baseline during the first 48 hour of life. FT4 and FT3 values at 3, 24, and 48 hours were significantly higher in control group than in group II and group III.
Cord blood thyroid-stimulating hormone, FT4 and FT3 levels were not statistically different in the three groups. A rapid increase in thyroid-stimulating hormone values by 3 hour after delivery (to a mean SD of 16.6 3, 18.0 t.1.2 and 17.0 3.0 ul/ml in group, I, II, and III, respectively), followed by a progressive thyroid-stimulating hormone decline to levels similar to baseline over the following 48 hours, was noted in all three groups of subjects.
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