Neurodevelopment Outcome, Preterm, SGA and Growth, Thyroid Function
Conditions
Brief summary
The primary objective of this clinical trail is to evaluate whether early supplementation of levothyroxine (L-T4) at a dosage of 8 ug/kg/d, initiated in the second week of life, improves physical growth and neurodevelopmental outcomes at 2 years of corrected age in Small for Gestational Age (SGA) infants with birth weights \< 1500g and TSH levels between 6 and 20 mIU/ml. Preterm infants in the intervention group will receive 8 ug/kg/d of L-T4, while the control group will receive no supplementation. Physical growth will be assessed through height, weight, and head circumference, while neurodevelopmental status will be evaluated using the Bayley-IV scales and cranial MRI imaging findings.
Interventions
The intervention group will receive oral levothyroxine (L-T4) initiated on postnatal day 14 at a starting dose of 8 ug/kg/day. Thyroid function will be monitored every 2-4 weeks until 36 weeks postmenstrual age or hospital discharge, with subsequent follow-up at corrected ages of 40 weeks, 3, 6, 12, 18, and 24 months. The L-T4 dosage will be dynamically titrated to achieve therapeutic targets of TSH \< 5 mIU/L and FT3/FT4 levels within the upper 50% of the age-specific reference range. Treatment will be discontinued if therapeutic targets are sustained at a dosage below 2 ug/kg/day or if FT3/FT4 levels exceed the upper limit of normal.
Sponsors
Study design
Eligibility
Inclusion criteria
* Preterm infants born Small for Gestational Age (SGA) with a birth weight \< 1500g; * Admitted to a participating Neonatal Intensive Care Unit (NICU) within 7 days of birth; * Serum concentrations of TSH, FT4, and FT3 are measured weekly during the first and second weeks of life,any single TSH measurement during this period is between 6 and 20 mIU/mL; * Written informed consent obtained from the parents.
Exclusion criteria
* Diagnosis of Congenital Hypothyroidism (CH) with serum TSH \> 20 mIU/mL within the first 2 weeks of life and receiving L-T4 treatment; * Persistent serum TSH \< 6 mIU/mL throughout the first 2 weeks; * Elevated thyroid hormone levels(T3, T4, FT3, or FT4) above the reference range within the first 2 weeks; * Diagnosis of Grade III or IV Intraventricular Hemorrhage (IVH) within the first 2 weeks of life; * Presence of major congenital malformations of vital organs or known chromosomal/genetic disorders; * History of maternal thyroid disease or maternal use of thyroid-related medications.
Design outcomes
Primary
| Measure | Time frame |
|---|---|
| Cognitive function evaluated by Bayley-IV | At 24 months corrected age |
| Motor function evaluated by Bayley-IV | At 24 months corrected age |
| Language function evaluated by Bayley-IV | At 24 months corrected age |
| Social-Emotional evaluated by Bayley-IV | At 24 months corrected age |
| Adaptive behavior evaluated by Bayley-IV | At 24 months corrected age |
| Body length(cm)assessed by the WHO 0-5 years Child Growth Standards. | At 24 months corrected age |
| Head circumference(cm)assessed by the WHO 0-5 years Child Growth Standards. | At 24 months corrected age |
| Weight(kg)assessed by the WHO 0-5 years Child Growth Standards. | At 24 months corrected age |
Secondary
| Measure | Time frame |
|---|---|
| the incidence of neonatal morbidities (EUGR、PNAC、MBDP、Moderate to severe BPD、Stage III or higher ROP)during the initial hospitalization | at 36 weeks of postmenstrual age |
| All-cause Mortality | At 24 months corrected age |
Countries
China