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High incidence of thyroid dysfunction in preterm infants.

Chung HR, Shin CH, Yang SW, Choi CW, Kim BI, Kim EK, Kim HS, Choi JH - J. Korean Med. Sci. (2009)

Bottom Line: We analyzed the effects of gestational age, systemic diseases, and nutrition on the development of thyroid dysfunction.Twelve infants had moderately elevated TSH (TSH 10-30 microU/mL) with normal fT4 levels after 1 week of postnatal life.The history of undergone surgical procedure which needed iodine containing disinfectants was significantly frequent in the infant with hypothyroidism and transient TSH elevation.

View Article: PubMed Central - PubMed

Affiliation: Department of Pediatrics, Seoul National University Bundang Hospital, Seongnam, Korea.

ABSTRACT
To determine the validity of a repeat thyroid function test for preterm infants, and to investigate factors that influence thyroid function of preterm infants, thyroid functions of 105 infants born at <32 weeks' gestational age were evaluated. Initial serum free thyroxine (fT4) and thyrotropin (TSH) levels were measured during the first 10 days of life, and repeated tests were performed more than 2 weeks apart. We analyzed the effects of gestational age, systemic diseases, and nutrition on the development of thyroid dysfunction. Thirty-one infants (30%) had low fT4 levels (<0.7 ng/dL) in the absence of elevated TSH levels (<7 microU/mL). Thirteen infants (12%) had hypothyroidism (fT4 <0.7 ng/dL, TSH >or=10 microU/mL) and mean age at diagnosis was 28+/-17 days. Twelve infants had moderately elevated TSH (TSH 10-30 microU/mL) with normal fT4 levels after 1 week of postnatal life. The history of undergone surgical procedure which needed iodine containing disinfectants was significantly frequent in the infant with hypothyroidism and transient TSH elevation. Repeated thyroid function tests are necessary for preterm infants, even though they initially show normal thyroid function, and are especially important for infants who have been exposed to excessive or insufficient levels of iodine.

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Serum free T4, TSH, T3 concentration of 85 preterm infants during first 2 months after birth, grouped by gestational age. 20 infants who received L-thyroxine replacement were excluded. ●, <28 weeks (n=27); □, 28-30 weeks (n=32); ▲, 30-32 weeks (n=26).
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Figure 1: Serum free T4, TSH, T3 concentration of 85 preterm infants during first 2 months after birth, grouped by gestational age. 20 infants who received L-thyroxine replacement were excluded. ●, <28 weeks (n=27); □, 28-30 weeks (n=32); ▲, 30-32 weeks (n=26).

Mentions: Most infants born at <28 weeks' gestation had low free T4 concentrations during the first week of postnatal life. Serum free T4 levels gradually increased, and at 2 months of life, reached levels equal to those of term infants. Infants of low gestational age had a tendency to show low TSH concentrations during the first week of postnatal life. TSH levels had a tendency to increase transiently between the second and fourth weeks of life in all groups. T3 concentrations gradually increased during the first 2 months after birth in all infants (Fig. 1).


High incidence of thyroid dysfunction in preterm infants.

Chung HR, Shin CH, Yang SW, Choi CW, Kim BI, Kim EK, Kim HS, Choi JH - J. Korean Med. Sci. (2009)

Serum free T4, TSH, T3 concentration of 85 preterm infants during first 2 months after birth, grouped by gestational age. 20 infants who received L-thyroxine replacement were excluded. ●, <28 weeks (n=27); □, 28-30 weeks (n=32); ▲, 30-32 weeks (n=26).
© Copyright Policy - open-access
Related In: Results  -  Collection

License
Show All Figures
getmorefigures.php?uid=PMC2719190&req=5

Figure 1: Serum free T4, TSH, T3 concentration of 85 preterm infants during first 2 months after birth, grouped by gestational age. 20 infants who received L-thyroxine replacement were excluded. ●, <28 weeks (n=27); □, 28-30 weeks (n=32); ▲, 30-32 weeks (n=26).
Mentions: Most infants born at <28 weeks' gestation had low free T4 concentrations during the first week of postnatal life. Serum free T4 levels gradually increased, and at 2 months of life, reached levels equal to those of term infants. Infants of low gestational age had a tendency to show low TSH concentrations during the first week of postnatal life. TSH levels had a tendency to increase transiently between the second and fourth weeks of life in all groups. T3 concentrations gradually increased during the first 2 months after birth in all infants (Fig. 1).

Bottom Line: We analyzed the effects of gestational age, systemic diseases, and nutrition on the development of thyroid dysfunction.Twelve infants had moderately elevated TSH (TSH 10-30 microU/mL) with normal fT4 levels after 1 week of postnatal life.The history of undergone surgical procedure which needed iodine containing disinfectants was significantly frequent in the infant with hypothyroidism and transient TSH elevation.

View Article: PubMed Central - PubMed

Affiliation: Department of Pediatrics, Seoul National University Bundang Hospital, Seongnam, Korea.

ABSTRACT
To determine the validity of a repeat thyroid function test for preterm infants, and to investigate factors that influence thyroid function of preterm infants, thyroid functions of 105 infants born at <32 weeks' gestational age were evaluated. Initial serum free thyroxine (fT4) and thyrotropin (TSH) levels were measured during the first 10 days of life, and repeated tests were performed more than 2 weeks apart. We analyzed the effects of gestational age, systemic diseases, and nutrition on the development of thyroid dysfunction. Thirty-one infants (30%) had low fT4 levels (<0.7 ng/dL) in the absence of elevated TSH levels (<7 microU/mL). Thirteen infants (12%) had hypothyroidism (fT4 <0.7 ng/dL, TSH >or=10 microU/mL) and mean age at diagnosis was 28+/-17 days. Twelve infants had moderately elevated TSH (TSH 10-30 microU/mL) with normal fT4 levels after 1 week of postnatal life. The history of undergone surgical procedure which needed iodine containing disinfectants was significantly frequent in the infant with hypothyroidism and transient TSH elevation. Repeated thyroid function tests are necessary for preterm infants, even though they initially show normal thyroid function, and are especially important for infants who have been exposed to excessive or insufficient levels of iodine.

Show MeSH
Related in: MedlinePlus