Table 5 Results of the studies on the relationship between THOP and neurodevelopmental outcomes
Source and study type | Sample size | Supplementary strategy and assessment age | Outcomes |
|---|---|---|---|
Sze May Ng et al. [30], randomized clinical trials | < 28 weeks of gestation, 30 infants treated, 29 infants untreated, | 8 µg/kg at first day to 32 weeks of gestation, 42 months | Motor, language, and cognitive functions were significantly higher in Bayley III development tests in the group given thyroxine treatment |
Suzumura et al. [31], cohort study | < 28 weeks of gestation, 54 infants (first period, untreated and not measurement), 60 infants (second period treated, FT4 < 0.8 ng/dl was) | 5–10 µgr/kg mainly at 7 days of age, corrected age of 18 months | Incidence of cerebral palsy was lower in the treated group |
< 30 weeks of gestation, 100 infants treated 100 infants untreated | 8 µg/kg/day at first day to 42th day, 2 and 10 years | At 2 years of age, 27 gestational weeks (25–26 wk), the mean IQ was 18 points higher, whereas in the group born between 27–30 weeks mean IQ was 10 points lower in the treated groups at 2 years of age At 10 years of age school success and motor development were higher in the treated groups who were born earlier than 27 weeks of gestation (25–26 wk) and 28 weeks respectively compared to placebo groups. However, in the treatment group development was poor in premature infants born at 29 weeks of gestation and needed more special education | |
Chowdhry et al. [34], randomized clinical trials | 25–28 weeks of gestation and birth weight < 1250 g, 11 treated 12 untreated | 10 µg/kg/day, at 14 to 66 days, corrected age of 12 months | At the 28th and 36th weeks of life, there was no difference in PDA, NEC, retinopathy, and anthropometric measurements Data regarding neurodevelopment was insufficient in this study |
Uchiyama et al. [35], randomized clinical trials | Unknown, Birth weight < 1500 g 25 infants treated, 45 infant untreated | 5 µg/kg/day at 14 to 42 days, corrected age of 18 months | Anthropometric measurements, cerebral palsy, and neurodevelopmental indicators were indifferent between L-T4 treated and not treated groups |
Vanhole et al. [36] randomized clinical trials | 25–30 weeks of gestation, 20 treated 20 untreated | 20 µg/kg/day at 1 to 14 days, age of 7 months | LT4 treatment did not affect neonatal mortality and morbidity, and neurodevelopment |
Cochrane investigation [37], metaanalysis | 4 study, 318 infants | LT4 treatment was started in the first 48 postnatal hours, however different doses, treatment modalities, and durations | These studies showed that prophylactic LT4 treatment did not have any effect on neonatal mortality, morbidity, and neurodevelopment |
Dilli et al. [38], cohort study | < 32 weeks of gestation and < 1500 g, 16 infants were THOP, 40 infants were euthyroid | No treatment, corrected age of 18 to 24 months | THOP was not associated with increased risk of cerebral palsy or decreased mental development index and psychomotor development index scores |
Hollanders et al. [22], cohort study | < 32 weeks of gestation and/or < 1500 g 120 infants were THOP, 278 infants were nonhypothyroxinemic | No treatment, 19 years of age | There was no relation between hypothyroxinemia and neurodevelopment |