Thyroid function in preterm infants 27-29 weeks of gestational age during the first four months of life: results from a prospective study comprising 80 preterm infants.
OBJECTIVE
Assessment of thyroid function in preterm neonates (PTN) 27-29 weeks of gestational age.


METHODS
80 PTN, gestational age 27 weeks in 24, 28 weeks in 28, and 29 weeks in 28. Neonates were classified as healthy (n=17) or sick (n=63). Measurement of serum TSH, free T4, T4, T3 and rT3 in the mother and in the cord at the time of delivery, and in the infant at 1 hour, 24 hours, 1 week, 3 weeks, and 2 and 4 months of postnatal age.


RESULTS
In healthy and sick preterms, TSH values peaked at 1 hour and decreased thereafter. Healthy PTN presented a peak in free T4 values at 24 hours that was not observed in sick neonates. Sick PTN had a lower TSH peak and lower free T4 values at 24 hours and 1 week than healthy ones (p < 0.05). Healthy PTN 27-29 weeks had lower TSH peak at 1 hour and lower free T4, T3 and T4 values during the first 2 months than healthy PTN 30-35 weeks (PTN30-35w) previously evaluated (p < 0.05). However, at all postnatal times healthy preterms had free T4 values above -2 SD of the mean values of healthy PTN30-35w. A wide range of free T4 values was observed in the sick group. Free T4 values above -2 SD of the mean values of healthy PTN30-35w were detected in a high proportion of sick PTN (58.3% at 24 hours, 73.5% at 1 week, 93.9% at 3 weeks, 85.1% at 2 months and 100% at 4 months).


CONCLUSIONS
Prematurity and disease influence thyroid function, and consequently thyroid function should be individually assessed in preterms 27-29 weeks of gestation during the first 2 months of life.
Clemente
María
M
Pediatric Endocrine Service, Children's Hospital Vall d'Hebron, Autonomous University of Barcelona, Spain. mclement@vhebron.net
Ruiz-Cuevas
Pilar
P
Carrascosa
Antonio
A
Potau
Neus
N
Almar
Jordi
J
Salcedo
Salvador
S
Yeste
Diego
D
D001724:Birth Weight / Q000502:physiology; D016208:Databases, Factual / Q000706:statistics & numerical data; D005865:Gestational Age; D006801:Humans; D007231:Infant, Newborn / Q000097:blood; D007232:Infant, Newborn, Diseases / Q000097:blood / Q000175:diagnosis / Q000453:epidemiology; D007234:Infant, Premature / Q000097:blood* / Q000502:physiology*; D008137:Longitudinal Studies; D015997:Neonatal Screening / Q000379:methods; D011446:Prospective Studies; D013030:Spain / Q000453:epidemiology; D013960:Thyroid Function Tests; D013961:Thyroid Gland / Q000502:physiology*; D013972:Thyrotropin / Q000097:blood; D013974:Thyroxine / Q000097:blood; D013997:Time Factors; D014284:Triiodothyronine / Q000097:blood; D014285:Triiodothyronine, Reverse / Q000097:blood
D014284:Triiodothyronine; D014285:Triiodothyronine, Reverse; D013972:Thyrotropin; D013974:Thyroxine