The Clinical Studay Of Transient Hypothyroxinaemia Of Preterm

Objective: To investigate the relationship between thyroid hormone level of preterm and gestational age(GA), birth weight, and the effect of supplying L-T4 for THOP.The objective is to assertain the demanding of supplying Levothyroxine for preterm infants,especially for ≤34W preterm infants.Methods: To detect serum thyroxine levels of preterm infants and term infants by means of Electro chemilu minesence immunoassay(ECLI), 60 preterm infants of the SHANGDONG PROVINCE Hospital were selected as study groups including two groups acording to GA: A, ≤34w (n=30) and B, > 34w (n=30) , group A and group B were respectively randomly divided into A1,A2and B1,B2 who matched for maternal age and gestational age. 20 normal term infants of the SHANGDONG PROVINCE Hospital were selected as control group (TBI). They were defineded as group TBIa before treating,while after treating as group TBIb. Al including 15 infants as control without Levothyroxine, while A2 including 15 infants were supplied with Levothyroxine (L-T4) , and the same treating with B. Estimating the effect of supplying Levothyroxine for preterm infants by scores of behavioral neurological assessment. All infants of group B and TBIa were estimated 3 days after birth for the first time; all preterm were estimated by scores of behavioral neurological assessment 2 weeks later, and 20 term infants with same age (TBIb) also estimated.Results: 1. Thyroxine levels (TSH,FT₃,FT₄) of term infants are higher than that in preterm infants; there were obvious statistical differences(P<0.01). Thyroxine levels increased with the increasing of age and weight . There was a positive correlation between the thyroxine' levels (TSH,FT₃,FT₄) and gestational age,birth weight.2. 2 weeks later, the thyroid hormone (FT₃,FT₄)level of the groups respectively higher than before especially ft3, and there were statistical differences except groupAl (p<0.05); Thyroid hormone level of the groups with supplying of the Levothyroxine (A2, B2) higher than that of control groups without supplying Levothyroxine respectively, there were obvious statistical differences (p<0.01). The difference between thyroid hormone levels of A2 and B1 were not obvious(p > 0.05) while the difference between levels of B1 and TBIb were not obvious. Buthe differencebetween levels of B2 and TBIb were not obvious, (p > 0.05).3. 2 weeks later, TSH raised significantly except B2, the diffence was obvious (p<0.05 or p<0.01). A2 had higher TSH level than A1, while B1 had higher TSH level than B2, there were obvious statistical differences (p<0. 01) respectively; the TSH of A2 raises slowler than that of B1 (p<0.01). but the TSH of Blhad not diffence with TPIb (p > 0.05).4. Scores of behavioral neurological assessment of B was lower than that of TPIa(p<0.01). 2 weeks later scores of preterm infants who were supplied with Levothyroxine were higher than that of the groups without supplying (p<0.01). Scores of A1 and A2 were lowler than that of B1 and B2 (p<0.01) respectively, and scores of B2 was still lower than TPIb,.p<0.01).Conclusions: 1.There are positive correlation between thyroxine levels and GA,BW. It indicates that the earlier the infant was delivered, the higher the risk of THOP was . The change of TSH can't reflect the true thyroxine levels of little preterm infants.so we can't estimate THOP by TSH only2. Supplying Levothyroxine can increase the thyroid hormone (FT₃,FT₄)level of preterm infants,and the lower of GA and BW for preterm infants was, the more obvious increasing was. Preterm infants especially ≤34w should be supplied with Levothyroxine .3. The improving of scores of behavioral neurological assessment for preterm infants with THOP by supplying Levothyroxine show the effect of supplying. We can supply Levothyroxine to preterm infants with THOP. especially ≤34w preterm infants.