The Changes Of Thyroid Hormone Level During The Neonatal Peroid And The Analysis Of Associated Factors

Objective:To investigate the changes of thyroid hormone levels in different gestational age and influnence factors.Methods:165 neonates who were hospitalized in the second affiliated hospital of kunming medical university between December in 2015 and December in 2016.They were divided into A?B?C?D?E groups according to gestational age,They were gestational age<32 weeks,32weeks<gestational age<34weeks,34weeks?gestational age<37 weeks,small for gestational age,term infant respectively.Serum thyroid stimulating hormone(TSH)?triiodothyronine(T3)?free triiodothyronine(FT3)?thyroxine(T4)?free thyroxine(FT4)were detected by radioimmunoassay in delivered infants who were extracted 2 ml venous blood in the morning of 3 to 7 days and 8 to 14 days after birth.Record the type of common disease of 165 neonates(pneumonia,sepsis,asphyxia,NRDS,etc)?the use of drug(dopamine,albumin,phenobarbital)as well as the general situation,according to the results of the thyroid function is divided into normal and abnormal groups,the diagnostic criteria of thyroid dysfunction:(1)the blood TSH was increased,FT4 was normal.(2)FT4 was decreased,TSHwas normal or decreased.(3)T3 was decreased,T4 was normal or decreased,FT4 was normal or increased,TSH was normal.(4)TSH was increased,FT4 was decreased.(5)TSH was decreased,T3?T4was increased.Thyroid hormone levels in different gestional age and different weeks of age were compared respectively.The influence factors of thyroid hormones were analyzed by binary logistic regression analysis.Results:1?The TSH values of A?B?C?D?E groups in 3 to 7 days after birth were 5.43 ± 5.33mIU/L?5.72 ± 5.15mIU/L?5.16 ± 3.76mIU/L?4.79 ± 3.98mIU/L?4.36 ± 2.46mIU/L,TSH values in 8 to 14 days after birth were 6.55 ± 4.94mIU/L?8.14±4.90mIU/L?10.27±8.35mIU/L?8.51±9.14mIU/L?8.54±5.18mIU/L,the result was that there was no significant different by using factor analysis of variance(P>0.05).2?The T3 values of A?B?C?D?E groups in 3 to 7 days after birth were0.73±0.21nmol/L?0.93±0.26nmol/L?1.02±0.27nmol/L?1.18±0.28nmol/L?1.27 ± 0.39nmol/L,T3 values in 8 to 14 days after birth were 0.94 ± 0.15nmol/L?1.1±0.19nmol/L?1.21 ± 0.24nmol/L?1.50 ± 0.40nmol/L?1.27 ± 0.40nmol/L,the result were statistically significant by using factor analysis of variance(P<0.05).3?The FT3 values of A?B?C?D?E groups in 3 to 7 days after birth were 2.33±0.57pmol/L?2.76±0.78pmol/L?2.93±0.72pmol/L?3.27±0.76pmol/L?3.54±1.00pmol/L,the result were statistically significant by using factor analysis of variance(P<0.05).FT3 values in 8 to 14 days after birth were2.84 ± 0.57pmol/L?3.25±0.52pmol/L?3.23± 0.58pmol/L?3.95 ± 0.95pmol/L?3.47± 0.96pmol/L,there was no significant different by using factor analysis of variance(P>0.05).4.The T4values of A?B?C?D?E groups in 3 to 7 days after birth were 53.87±5.73nmol/L?71.09±22.39nmol/L?85.97±25.02nmol/?102.75± 25.38nmol/L?99.96±25.77nmol/L,the result were statistically significant by using factor analysis of variance(P<0.05).T4 values in 8 to 14 days after birth were 68.65±16.79nmol/L?73.68±15.43nmol/L?82.14±25.37nmol/L?98.66±17.33nmol/L?90.29±30.47nmol/L,there was no significant different by using factor analysis of variance(P>0.05).5?The FT4values of A?B?C?D?E groups in 3 to 7 days after birth were9.53±2.73pmol/L?11.62±2.59pmol/L?12.85±3.16pmol/L?14.66±2.96pmol/L?16.14± 3.21 pmol/L,the result were statistically significant by using factor analysis of variance(P<0.05).FT4 values in 8 to 14 days after birth were 11..98 ± 2.54pmol/L?12.08±2.32pmol/L?12.18±3.07pmol/L?13.74±1.97pmol/L?4.07±2.59pmol/L,there was no significant different by using factor analysis of variance(P>0.05).6.In the normal thyroid function groups,birth weight was 2337.39 ± 500.39g?the period of using dopamine was 5.16±3.66days?the period of using albumin was 1.82±1.76days,in the abnormal thyroid function groups,birth weight was 1975.71±426.52g?the period of using dopamine was 6.53± 3.93days?the period of using albumin was 2.65±2.05days,the t test results had significant different(P<0.05).Compared with the chi-square test the male thyroid dysfunction rate was 66.7%and the famale thyroid dysfunction rate was 51.3%,the result was statistically significant(P<0.05).In the binary logistic regression analysis,the OR value of asphyxia was 2.624,P<0.05.Conclusions:1?Within one week after birth,The smaller the gestational age,the lower the level of thyroid hormones(T3?FT3?T4?FT4).With the increase of gestation age,the level of thyroid hormone gradually approaching the full-term infant.2?It was speculated that the factor that may affect thyroid function may be gestational age?gender?birth weight?disease(asphyxia)and medication(dopamine?albumin).3?Asphyxia may be one of the factors that affect the level of thyroid hormones in the newborns in one week after birth.