Thyroid Hormone and Thyrotropin Responses to Parturition in Premature Infants With and Without the Respiratory Distress Syndrome

摘要

Serum thyroxine (T4), triiodothyronine (T3), reverse triiodothyronine (rT3), thyrotropin (TSH), and thyroxine-binding globulin (TBG) concentrations were measured in well full-term infants (group 1), well premature infants (group 2), and premature infants with the respiratory distress syndrome (group 3). Samples were collected at birth and at 2, 12, and 24 hours after delivery. Significant increases in mean serum TSH concentrations occurred in all three groups two hours after delivery, but the two-hour levels measured in groups 2 and 3 were less than those in group 1 infants. Serum T4 concentrations increased significantly after delivery in groups 1 and 2 but not in group 3 newborns; mean TBG concentrations did not vary significantly in any of the groups. Serum T4, concentrations increased significantly at two hours in all three groups but were significantly depressed at 12 and 24 hours in group 3 infants. Mean serum rT3, concentrations decreased after birth in group 2 and 3 in contrast to group 1 newborns; the mean value increased significantly between 2 and 24 hours in group 3 infants. The pattern of decreasing senrum T3 and increasing rT3 concentrations in group 3 infants between 2 and 24 hours resembles the pattern of change in triiodothyronines in ill adult patients, which suggests that these variations are due primarily to illness and not to prematurity.