Analysis and treatment on transient hypothyroidism in preterm infants

Abstract

Objective To explore the thyroid function and curative effect with thyroid hormone supplementation in premature infants.Methods Serm thyroid-stimulating hormone(TSH),total thyroxine (TT4),free thyroxine(FT4),total triodothyrorine(TT3) and free triodothyrorine(FT3) were detected in 165 premature infants.Premature infants with low TT4 and low FT4 were divided into Levothyroxine group and control group according to clinical symptom; premature infants with low TT3 were randomized into Levothyroxine group and control group.Levothyroxine group received Levothyroxine,TSH,TT4,FT4,TT3 and FT3 were detected once a week.Results ①The thyroid function in the premature infants was transiently low.The shorter the gestational age,the lower the thyroid function.The incidence rate of 28 ～ 30 weeks of gestational age,30 ～ 32 weeks of gestational age,32 ～ 34 weeks of gestational age and 34 ～ 36 weeks of gestational age were 77.27％,75％,39.47％ and 32.47％ respectively.② symptom disappeared after Levothyroxine supplementation in premature infants with low TT4 and low FT4.Time of reaching normal range of the thyroid hormone in Levothyroxine group was significantly shorter than that of control group.The normal rate of serum concentrations of FT4,T4 on the 14th day after birth in Levothyroxine group was 100％,That in control group was 44.4％.(P =0.00).③ Time of reaching normal range of the thyroid hormone was not significantly different between Levothyroxine group with low TT3 and control group with low TT3.The normal rate of serum concentrations of TSH,T3 on the 28th day after birth in Levothyroxine group was 15％,while that in control group was 10％ (P=1.00).Conclusion The thyroid function in the premature infants is transiently low.The shorter the gestational age,the lower the thyroid function.Thyroid hormone replacement therapy in premature infants with a symptom of transient hypothyroxinemia is useful. Key words: Premature infants; Thyroid function; Transient hypothyroidism