Effect of Perinatal Asphyxia on Thyroid Hormones

Abstract

ResumoObjetivo: verificar o efeito da asfixia perinatal sobre os hormô-nios tireóideos.Métodos: foi realizado um estudo de caso-controle, no hospital de Clínicas de Porto Alegre, envolvendo 17 recém-nascidos a termo asfixiados (A) e 17 não-asfixiados (N), pareados conforme a cor, sexo, tipo de parto, idade gestacional e peso de nascimento. Foram coletados T4, T3, T4 livre, T3 reverso e TSH do sangue do cordão e do recém-nascido com 18 a 24 horas de vida, entre os que sofreram ou não asfixia perinatal.Resultados: no sangue de cordão, não houve diferença na dosagem dos hormônios tireóideos, com exceção do T3 reverso, que foi mais elevado no grupo que sofreu asfixia [mediana (percentis 25-75):A= 2(1,4-2); N= 1,41(1,13-1,92); p=0,037]. Com 18 a 24 horas de vida, foram significativamente menores no grupo de asfixiados, com exceção do T3 reverso, que foi semelhante entre os dois grupos [média ± DP: T4 A= 9,79 ± 2,59; N=14,68 ± 3,05; p<0,001/ mediana T3 A= 40,83(37,4-80,4); N= 164(56,96-222,5); P=0,003/ média ± DP T4 livre A=1,85 ± 0,92; N= 2,8 ± 0,74; p=0,004/ mediana T3 reverso A= 1,54(1,16-1,91); N= 1,31(0,87-2); p=0,507/ TSH A= 9,1(6,34-12,95); N=14,5(12,9-17,85); p=0,008].Conclusões: nossos dados sugerem que os níveis diminuídos de T4, T4 livre e T3 no recém-nascido asfixiado com 18 a 24 horas de vida são secundários aos níveis diminuídos de TSH. Além disso, os valores baixos de T3 e normais de T3 reverso podem refletir alteração no metabolismo periférico do T4.J Pediatr (Rio J) 2001; 77 (3): 175-78: hormônios da tireóide, asfixia perinatal, síndrome do doente eutireóideo. AbstractObjective: to verify the effect of perinatal asphyxia on thyroid hormone levels in term newborn infants.Methods: we carried out a case-control study with 17 term and asphyxiated (A) and 17 term and control (N) newborn infants at the Hospital de Clínicas de Porto Alegre. Patients were paired according to color of skin, sex, mode of delivery, gestational age, and weight at birth. We collected plasmatic T4, T3, free T4, reverse T3, and TSH of the umbilical cord after 18 to 24 hours of life and from asphyxiated and control newborn infants.Results: there were no differences in thyroid hormones of cord blood, with the exception of reverse T3, which was higher in A than in controls [median (percentile 25-75): A= 2(1.4-2); N= 1.41 (1.13-1.92); P=0.037)]. Thyroid hormone levels were lower in A than in controls on 18-24-hour after birth samples, except for reverse T3, which was similar in both groups [average ± SD: T4 A= 9.79 ± 2.59; N=14.68 ± 3.05; P<0.001; median T3 A= 40.83 (37.4-80.4); N= 164 (56.96-222.5); P=0.003; average ± SD: free T4 A=1.85 ± 0.92; N= 2.8 ± 0.74; P=0.004; median: reverse T3 A=1.54 (1.16-1.91); N=1.31(0.87-2); P=0.507; TSH A=9.1 (6.34-12.95); N=14.5(12.9-17.85); P=0.008].Conclusions: our data suggests that lower T4, free T4, and T3 levels are secondary to lower TSH levels in asphyxiated newborns; also, peripheral metabolism of T4 in asphyxiated infants can be altered due to low T3 and normal reverse T3 levels.J Pediatr (Rio...

A Study of Effect of Perinatal Asphyxia on Thyroid Hormone in Neonates

“…Similar results were observed by Pereira DN et al, 6 Borges et al 7 observed that mean value of FT3, and FT4 levels were significantly lower at 24 hrs and 48 hrs in the asphyxiated group than the control group but the mean levels of TSH were similar. In contrast to all studies, Franklin R C et at, 4 found no significant correlation in birth asphyxia and thyroid profile in newborn.…”

“…These finding were comparable to Borges et at al, 7 and Pereira DN et al 6 whereas Thivoric HF 3 found that mean value of T 3 andT4 were significantly lower in cord blood of asphyxiated newborns compared to healthy term babies.…”

“…[3][4][5][6] most of these studies conducted in developed countries and cord blood pH is used to define asphyxia, while in India most of the study used clinical criteria like APGAR score to define birth asphyxia.…”

Effect of Perinatal Asphyxia on Thyroid Stimulating Hormone and Thyroid Hormones

“…Our observations are similar to study done by Pereira et al; [11] they had 17 cases of birth asphyxia and 17 controls. The median value of S.T3 between 18-24 hours of life in controls were 164.00 (56.96-222.5) ng/dl as compared to 40.8(37.4-80.4) ng/dl in cases (P= 0.003).The Mean value of S.FT4 level in cases was 1.85± 0.92 ng/dl as compared to 2.8± 0.74 U/L in the control group (P = 0.004).…”

“…Our results are similar to Pereira et al; [11] they found that hormone alterations were more frequent in neonates presenting with moderate/severe hypoxicischemic encephalopathy. They compare asphyxiated babies with and without moderate/severe encephalopathy with control group, and found that asphyxiated babies with moderate/severe encephalopathy presented a significantly lower FT4 mean (1.44±0.63ng/dl) than those without disease (2.81±0.74ng/dl).…”