Thyroid FunctionPretermSGA and GrowthNeurodevelopment Outcome
Investigational drug(s) / intervention(s)
Levothyroxine Sodium (LT4) Tablets
Levothyroxine Sodium (LT4) Tablets: 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.
Study 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.
Eligibility
Sex
ALL
Min age
2 Weeks
Max age
2 Weeks
Healthy volunteers
No
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.
Primary outcome measure(s)
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
Trial sites (1)
Facility
City
Region
Status
Shandong Provincial Hospital Affiliated to Shandong First Medical University
This page summarises publicly available registry data for informational purposes — not medical advice. Eligibility is determined by each study team; patients should discuss participation with their clinician.
We use cookies to analyse site traffic and improve your experience. With your consent, we may also use cookies for advertising. You can change your choice at any time.