Background:
Whether  hypothyroxinemia of prematurity is associated with delayed development and cerebral palsy is controversial. Predictive value of late thyroid function tests in VLBW infants, after 2 weeks of life, for long term neurodevelopment is contentious.

Objective:
To compare 5 year neurodevelopmental outcomes of VLBW infants with hypothyroxinemia of prematurity against those without. To review predictive values of cord TSH, predischarge thyroid function at term/near term for neurodevelopment and growth at 5 years.

Methods:
Retrospective cohort study in a single tertiary neonatal centre of VLBW infants admitted between 2008 to 2011. Routine cord TSH and pre-discharge thyroid function tests at term were analysed. Additional thyroid function tests performed inpatient, as well as the lowest fT4 and highest TSH, were also analysed.

The outcome data at 5 years old included growth parameters, WPPSI III, Bracken School Readiness Assessment, VABS and Beery Test of Visual-Motor Integration. A multi-logistic regression model was used incorporating gestation, gender, duration of NICU and the individual thyroid tests looking at prediction of neurodevelopment.

Results:
A total of 105 VLBW infants were reviewed. Mean gestation was 26.6 weeks, birthweight 1.040 kg. Cord TSH (n=87) predicts WPPSI full scale IQ, Bracken School readiness, Beery VMI and also weight and height. For thyroid function tests done before discharge (median 37.3 weeks, IQR 1.3 weeks), fT4 predicts school readiness and Beery VMI, while TSH at discharge predicts WPSSI verbal IQ, processing speed, shape mastery and VABS daily living skills. Thyroxine replacement babies had worse full scale IQ, processing speed, performance score, number counting mastery and Beery VMI abnormalities. No significant differences in the 5 year adverse neurodevelopmental outcome were found, when analysed between hypothyroxinemia of prematurity and control.

Conclusion:
Different thyroid function tests, even in VLBW infants without congenital hypothyroidism, predict for different aspects of neurodevelopment and growth at 5 years. However, hypothyroxinemia of prematurity was not associated with neurodevelopmental delay.

08 - HYPOTHROXINEMIA OF PREMATURITY WAS NOT ASSOCIATED WITH ADVERSE 5-YEAR NEURODEVELOPMENTAL OUTCOME IN VERY LOW BIRTH WEIGHT (VLBW) INFANTS