Perinatal Factors Affecting Thyroid Stimulating Hormone(TSH) and Thyroid Hormone Levels in Cord Blood

Kim, Eun Young; Park, Sang Kee; Song, Chang Hun; Lim, Sung Chul

Abstract

PURPOSE
The aim of the this study was to evaluate the effect of various perinatal conditions on TSH and thyroid hormone levels in cord blood.
METHODS
Cord blood samples were collected from 130 neonates immediately after birth. TSH, T3, and free T4 levels were measured by the radioimmunoassay(RIA) method. The effects of gestational age, sex, birth weight, delivery method, perinatal asphyxia, maternal diabetes mellitus(DM), and preeclampsia on TSH and thyroid hormone levels were assessed by ANOVA test, Student t-test, and multiple regression analysis.
RESULTS
Birth weight and sex did not affect TSH and thyroid hormone levels. TSH level increased according to gestational age(P<0.05). TSH level was 4.42+/-0.66 microIU/mL in infants born vaginally, which was higher than that of cesarian section delivery(3.31+/-0.33 microIU/mL)(P<0.05). TSH level was 5.18+/-0.93 microIU/mL in asphyxiated newborns and 2.97+/-0.84 microIU/mL in non-asphyxiated newborns(P< 0.05). TSH level in infants with maternal DM(8.911+/-1.25 microIU/mL) was higher than that of infants without maternal DM(4.32+/-0.42 microIU/mL)(P<0.05). TSH level was 5.28+/-0.42 microIU/mL in infants with maternal preeclampsia and 3.65+/-0.46 microIU/mL in infants without maternal preeclampsia(P<0.05). Thyroid hormones were lower in infants with perinatal asphyxia(P<0.05). In asphyxiated infants, T3 level was 75.33+/-55.65 ng/mL and free T4 was 0.54+/-0.21 ng/mL. T3 and free T4 level was 109.85+/-41.77 ng/mL and 0.76+/-0.22 ng/mL each in infants without perinatal asphyxia. Among the perinatal factors, gestational age, 1 min Apgar score and maternal DM influenced TSH level independently.
CONCLUSION
In our study, cord blood TSH and thyroid hormone levels were affected by perinatal stress events.