Thyroid hormone levels in infants of diabetic mothers

ABSTRACT

Infants born to diabetic mothers have decreased activity of many metabolic pathways which might be regulated by thyroid hormone. Serum Thyrotropin [TSH], Thyroxine [T4], triiodothyronine [T3] and reverse T3 levels were measured in maternal and cord sera of twenty normal full term infants and thirty infants of diabetic mothers [I.D.M]. Thyroxine of diabetic mothers 9.4 +/- 1.2 micro g/dl was significantly less [P less than 0.005] than the mean T4 normal mothers 14.2 +/- 2.2 micro g/dl. Mean T3 of diabetic mothers [148 +/- 14 ng/dl] was significantly less [P less than 0.001] than that of normal mothers [184 +/- 13ng/dl]. Mean T4 of neonatal specimens was lower in infants of diabetic mothers [I.D.M] but this difference achieved statistical significance at the 12 hour sample [P less than 0.001]. Infants of I.D.M had significantly lower mixed cord serum T3 than control infants 60 +/- 5 ng/dl versus 96 +/- 18 ng/dl [P less than 0.001]. At each time interval, mean T3 concentration in infants of diabetic mothers was significantly lower than that of full term infants. Levels of reverse trioidothyronine [rT3] were significantly increased in cord blood of infants of diabetic mothers [186 +/- 9 ng/dl] versus cord blood of normal full term infants [150 +/- 10 ng/dl] [P less than 0.001]. These data open the way that maybe some of the metabolic alternations seen in neonates born to diabetic mothers may be due to decreased thyroid hormone levels during the first day of life