Abstract
BACKGROUND: Infants born at extreme prematurity are at high risk of developmental
disability. A major risk factor for disability is having a low level of thyroid
hormone described as hypothyroxinaemia, which is recognised to be a frequent
phenomenon in these infants. Derangements of critical thyroid function during the
sensitive window in prematurity when early development occurs, may have a range
of long term effects for brain development. Further research in preterm infants
using neuroimaging techniques will increase our understanding of the specificity
of the effects of hypothyroxinaemia on the developing foetal brain. This is an
explanatory double blinded randomised controlled trial which is aimed to assess
the effect of thyroid hormone supplementation on brain size, key brain
structures, extent of myelination, white matter integrity and vessel morphology,
somatic growth and the hypothalamic-pituitary-adrenal axis.
METHODS: The study is a multi-centred double blinded randomised controlled trial
of thyroid hormone supplementation in babies born below 28 weeks' gestation. All
infants will receive either levothyroxine or placebo until 32 weeks corrected
gestational age. The primary outcomes will be width of the sub-arachnoid space
measured using cranial ultrasound and head circumference at 36 weeks corrected
gestational age. The secondary outcomes will be thyroid hormone concentrations,
the hypothalamic pituitary axis status and auxological data between birth and
expected date of delivery; thyroid gland volume, brain size, volumes of key brain
structures, extent of myelination and brain vessel morphology at expected date of
delivery and markers of morbidity which include duration of mechanical
ventilation and/or oxygen requirement and chronic lung disease. Trial
registration Current Controlled Trials ISRCTN89493983.
disability. A major risk factor for disability is having a low level of thyroid
hormone described as hypothyroxinaemia, which is recognised to be a frequent
phenomenon in these infants. Derangements of critical thyroid function during the
sensitive window in prematurity when early development occurs, may have a range
of long term effects for brain development. Further research in preterm infants
using neuroimaging techniques will increase our understanding of the specificity
of the effects of hypothyroxinaemia on the developing foetal brain. This is an
explanatory double blinded randomised controlled trial which is aimed to assess
the effect of thyroid hormone supplementation on brain size, key brain
structures, extent of myelination, white matter integrity and vessel morphology,
somatic growth and the hypothalamic-pituitary-adrenal axis.
METHODS: The study is a multi-centred double blinded randomised controlled trial
of thyroid hormone supplementation in babies born below 28 weeks' gestation. All
infants will receive either levothyroxine or placebo until 32 weeks corrected
gestational age. The primary outcomes will be width of the sub-arachnoid space
measured using cranial ultrasound and head circumference at 36 weeks corrected
gestational age. The secondary outcomes will be thyroid hormone concentrations,
the hypothalamic pituitary axis status and auxological data between birth and
expected date of delivery; thyroid gland volume, brain size, volumes of key brain
structures, extent of myelination and brain vessel morphology at expected date of
delivery and markers of morbidity which include duration of mechanical
ventilation and/or oxygen requirement and chronic lung disease. Trial
registration Current Controlled Trials ISRCTN89493983.
| Original language | English |
|---|---|
| Journal | BMC Pediatrics |
| Volume | 8 |
| Issue number | 26 |
| Publication status | Published - 2008 |