The Value of Neonatal Serum Thyroglobulin Determinations in the Follow-up of Patients with Congenital Hypothyroidism

ABSTRACT. Serum thyroglobulin was determined in 68 newborn infants with positive screening tests for congenital hypothyroidism. In 38 infants the diagnosis was confirmed (patients), but the remaining 30 were euthyroid at follow-up (controls). The mean thyroglobulin concentration at the age of 2 weeks did not differ significantly between the patients and the controls (179 vs. 125 μg/l). Thyroid scintigraphy was performed in 15 patients. All seven with thyroid aplasia, based on ^99mTc pertechnetate scintigraphy, had measurable thyroglobulin (> 2 μg/l) and thyroid hormones in their serum. This indicates that total absence of thyroid tissue is very rare in Swedish patients with congenital hypothyroidism. Scintigraphy based on ^99mTc does not permit detection of small amounts of thyroid tissue. The neonatal concentrations of thyroglobulin did not correlate with the results of Griffiths test at 3 years and are therefore not useful for prognosis of psychomotor development. We conclude that neonatal measurement of thyroglobulin is of limited value in the follow-up of patients with congenital hypothyroidism.     

SERUM α-FETOPROTEIN—A BIOCHEMICAL INDICATOR OF PRENATAL HYPOTHYROIDISM

ABSTRACT. Serum α-fetoprotein (AFP) was analysed at 10–30 days of age in infants with positive TSH screening tests for congenital hypothyroidism. These levels were significantly higher in infants with true positive screening tests than in those with false positive tests; 27 of 43 infants with congenital hypothyroidism had serum AFP levels above the age-related reference range. The postnatal rate of elimination of AFP from serum did not differ in hypothyroid and euthyroid infants, indicating that the difference in serum AFP was due to more extensive synthesis in hypothyroid individuals. The level of serum AFP was inversely correlated with the roentgenological skeletal maturation index. It is postulated that increased serum AFP is caused by prenatal hypothyroidism and that analysis of serum AFP is a valuable tool to identify those infants with congenital hypothyroidism who are at risk of neuropsychological sequelae.     

Food Intake and Growth of Infants between Six and Twenty-six Weeks of Age on Breast Milk, Cow's Milk Formula, or Soy Formula

ABSTRACT. In 59 normal infants attending well-baby clinics, food consumption was registered until 26 and growth until 52 weeks of age. They were either breast-fed or formula-fed with a cow's milk product or a soy protein product. The average consumption of breastmilk was 746, 796, 722 and 689 g/day at 6, 14, 22 and 26 weeks respectively. Bottle-fed infants received larger volumes, and at 6 and 14 weeks were the calculated total energy intakes significantly higher than in breast-fed infants. No differences were seen between the feeding groups with respect to length and the sum of four skin folds. The soy formula-fed children, who happened to be 200 g heavier at birth, had lower weight gains during the first 6 weeks than the other two groups. Thereafter, the average weights of the soy formula group did not differ from the other groups. At 3 months, the soy formula-fed children displayed a slower mineralisation and maturation of bone, but the difference was no longer significant when re-examined at 6 months. Formulas based on soy protein isolates seem to be acceptable as substitutes for cow's milk formulas in feeding normal infants.