Maternal and Neonatal Factors That Influence the Umbilical Cord Blood Thyroid-Stimulating Hormone Level

Ravi Bhatia, Gunjan Bhatia, Dinesh Rajwaniya, Priyanka Mishra, Kathit Gohel

Abstract

Aim: To understand various prenatal and perinatal factors that influence the umbilical cord blood (UCB) thyroid-stimulating hormone (TSH) level

Materials and Methods: In this cross-sectional study, the UCB TSH level was measured in 1,580 neonates born across a year. The TSH level was estimated using the chemiluminescence immunoassay method. All the neonates who had a UCB TSH level > 20 mIU/mL were called for a repeat thyroid profile test on day 7 of life.

Results: Of the 1,580 neonates, 61 neonates underwent the repeat thyroid profile test (recall rate: 3.86%). Of the 61 neonates, 1 neonate was diagnosed with hypothyroidism.

Upon evaluation of various prenatal and perinatal factors, the UCB TSH level was found to be significantly higher in the neonates delivered through vaginal delivery compared with those delivered through lower segment cesarean section. There was a significant difference in the UCB TSH level in neonates in whom LSCS was done for fetal distress compared with LSCS done on an elective basis. Male neonates had a significantly higher UCB TSH level compared with female neonates (P < .01). Multivariate analysis showed a positive correlation between TSH level and birth weight, mode of delivery, and reason for LSCS, and a negative correlation between UCB TSH level and sex, birth order, and Apgar score.

Conclusion: Perinatal stress and mode of delivery increase the UCB TSH level, which in turn increases the chances of false positive results. Hence, UCB TSH level should be interpreted considering prenatal and perinatal factors.