Abnormal responses to TRH in children born small for gestational age that failed to catch up.
BACKGROUND
Fifteen percent of small for gestational age (SGA) children remain short and undergo thyroid axis evaluations.


METHODS
We analyzed data on thyroid assessment of 58 SGA children. Five had primary autoimmune hypothyroidism. In the remaining 53 patients, TSH, free T4 (FT4), antithyroid antibodies and 90-min TRH test results were analyzed. Patients were grouped into G1 (n = 27; normal) and G2 (n = 26; abnormal) according to their response to the TRH test compared with 30 normal children.


RESULTS
No differences were found in chronological age, gestational age, or birth weight standard deviation score (SDS) between groups. G2 showed higher SDS BMI at consultation (p < 0.05). FT4 (ng/dl) levels were similar in all groups, while basal TSH levels were statistically different in G2 compared with G1 and controls. In 21 G2 patients treated with thyroxine, FT4 levels did not change, TSH normalized, BMI SDS and height remained unchanged.


CONCLUSIONS
These data suggest that in SGA short children thyroid abnormalities may occur. Some of them may be due to a different setting of the hypothalamic-hypophyseal-thyroid axis during intrauterine life. Intrauterine growth retardation may permanently influence endocrine systems by affecting their programming during development. Further follow-up is needed to confirm these findings and to assess their natural history and potential clinical impact.
Keselman
Ana
A
Hospital de Niños Ricardo Gutiérrez, CEDIE, Buenos Aires, Argentina. akeselman@cedie.org.ar
Chiesa
Ana
A
Malozowski
Saúl
S
Vieytes
Ana
A
Heinrich
Juan Jorge
JJ
de Papendieck
Laura Gruñeiro
LG
D000293:Adolescent; D015551:Autoimmunity; D001827:Body Height; D002648:Child; D002675:Child, Preschool; D005260:Female; D006130:Growth Disorders / Q000188:drug therapy*; D006801:Humans; D007030:Hypothalamo-Hypophyseal System / Q000502:physiology*; D007231:Infant, Newborn; D007236:Infant, Small for Gestational Age / Q000254:growth & development*; D008297:Male; D013961:Thyroid Gland / Q000276:immunology; D013972:Thyrotropin / Q000097:blood* / Q000627:therapeutic use
D013972:Thyrotropin