Transient hypothyroidism associated with prematurity, sepsis, and respiratory distress.

Serial TSH and T4 determinations were performed in sixty neonates admitted to our hospital for neonatal intensive care within a period of three months. Seven patients (12%) showed transient hypothyroidism on the basis of low T4 and high TSH values. Only one of these patients, who had meconium aspiration and pneumonia, did not have the respiratory distress syndrome. In addition, 4 of these patients had sepsis. All of the patients were born before 37 gestational weeks and had birth weights under 2200 g. In addition, two patients of this gestational age and birth weight group had a progressive fall of T4 to extremely hypothyroid values without simultaneous elevation of TSH. Two of the 5 patients who died had histological studies of their thyroids. These revealed colloid-depleted vesicles, desquamated epithelium, and prominent vascularisation of the thyroid. The results of this study show that early recognition and therapy of transient hypothyroidism may be live saving.