Evaluation of relationship between neonatal jaundice and incidence rate of congenital hypothyroidism in newborns at selected educational hospitals in Mashhad, Iran

Congenital hypothyroidism (CH) is one of the most urgent diseases of the newborns; with preventable complications, such as mental retardation, by early diagnosing and treatment. It is often asymptomatic, but it can induce severe and or prolonged jaundice. We aimed to assess relationship between neonatal jaundice, as a nonspecific clinical sign, and incidence rate of CH. This cross-sectional study was performed on 140 healthy term newborns affected jaundice that admitted to 4 selected educational Hospital in Mashhad, Iran. As CH causes both prolonged and severe hyperbilirubinemia, all 1-28- day old newborns with various causes of jaundice with total serum bilirubin values of > 10 mg/dl were included and evaluated for thyroid function tests. Thyroid-stimulating hormone (TSH)< 10 mu/l and thyroxin (T4) <7 µg/dl were considered as CH. Serum value of T4 was normal at 97.86% and low at 2.14%. 1.43% of newborns had serum level of TSH >10 mu/l. More investigation reavealed the incidence rate of hypothyroidism at approximately 1 case in 140 birth which means 7 cases in 1000 birth (7:1000). In present study, the incidence rate of CH was 7:1000. As usual, there is no clinical finding in CH at birth, so more attention should be paid to nonspecific signs of hypothyroidism that one of the earliest is severe or prolonged jaundice. Also, follow up should be considered for these newborns.