Neonatal Screening for Congenital Hypothyroidism through Dried Blood Spots: A Cross-sectional Study

Abstract

Introduction: Congenital Hypothyroidism (CH) is defined as the partial or complete loss of thyroid gland function present at birth. During the first 2-3 years of life, thyroid hormone plays a crucial role in brain development. If a baby is born with a deficiency of thyroid hormone (CH) and is not diagnosed and treated appropriately, it can lead to intellectual disability and growth retardation in the affected child. Aim: To screen newborns for CH using Dried Blood Spot (DBS) sampling. Additionally, the study aimed to compare mean TSH values between two comparison groups based on gender, birth weight, gestational age, and type of delivery. Materials and Methods: This cross-sectional study was conducted at Institute of Medical Sciences, Banaras Hindu University, Varanasi, Uttar Pradesh, India, from November 2021 to October 2022. A total of 250 live-birth newborns delivered either by Spontaneous Vaginal Delivery (SVD) or Lower Segment Caesarean Section (LSCS) were included in the study after obtaining written informed consent from their parents. Blood samples were obtained on DBS cards through heel prick in all newborns. TSH levels were assessed using a neonatal TSH sandwich ELISA kit. The cut-off value of TSH to label as screen positive was set at >20 mIU/L. A two-tailed Independent t-test was performed to compare mean TSH values between the two comparison groups based on gender, birth weight, gestational age, and type of delivery. Results: Out of the 250 babies, 137 (54.8%) were male and 113 (45.2%) were female. The gestational age ranged from a minimum of 29 weeks to a maximum of 41 weeks in both male and female babies. TSH levels in male babies ranged from 0.16 mIU/L to 10.27 mIU/L, with a mean value of 3.98±2.16 mIU/L. TSH levels were below 20 mIU/L in all 250 newborns, indicating negative screening results for CH in all the neonates. Conclusion: The results concluded that the serum levels of TSH obtained through heel prick were not statistically significant in both term and preterm newborns, as well as in Normal Birth Weight (NBW) and Low Birth Weight (LBW) newborns. Furthermore, there was no significant difference based on the type of delivery (SVD/LSCS) or the gender of the newborn (male or female).