Prevalence and Risk Factors Associated With Elevated Thyroid Stimulating Hormone in Late Preterm Newborns With Low Birthweight: A Cross-Sectional Study

Abstract

Introduction: Congenital hypothyroidism (CH) is seen more often in preterm and low birthweight infants. However, very few studies exist that explore the epidemiology and risk factors associated with CH, especially from the Indian subcontinent. Methods: A cross-sectional screening study was carried out on 240 low birthweight (<2.5 kg) and late preterm (34-36.6 weeks) newborns not requiring ventilator support over a period of 18 months. A total of 0.5 mL of venous sample was obtained on day 4 of life for analyzing thyroid stimulating hormone (TSH), tetraiodothyronine (T4), as well as tetraiodothyronine (T3) levels by an architect plus Chemiluminescence microparticle immunosorbent assay. Neonates with TSH values of more than 20 mIU/L were categorized as having elevated TSH. Results: Elevated TSH was seen in 10 (4.2%) neonates. The presence of maternal anemia ( P = .011), gestational diabetes mellitus (GDM) ( P < .001), and maternal hypothyroidism ( P < .01) was found to be significantly linked to elevated TSH levels. Other maternal comorbidities, gestational age, birthweight, as well as the nature of birth bore no significant relation with CH. Discussion: Elevated TSH was found to be common in late preterm and low birthweight newborns. Neonates of mothers suffering from hypothyroidism, advanced maternal age, GDM, and maternal anemia should be serially evaluated for thyroid abnormalities as they possess a significantly higher risk of having elevated TSH levels.