Aim: To determine the incidence of transient and permanent hypothyroidism in Babol, Iran.
Methods: The cross sectional study on 10,573 newborns who participated in a thyroid screening program in Babol between 2006 and 2008 was performed. It recalled patients who had been diagnosed in the initial screening program and treated for at least 3 years, discontinued their treatment for 4 weeks and then measured their plasma thyroid hormone concentrations. If their thyroid stimulating hormone (TSH) concentration was greater than 10 m/l they were considered to have permanent CH. T3 uptake, T4 and TSH were measured in venous blood samples. Other information collected and recorded included age, presence of diabetes, birth weight and gestational age at birth.
Results: The incidence of transient and permanent hypothyroidism in the studied infants was 5.7 and 20.8 per 10,000, respectively. The incidence of transient hypothyroidism in male and female infants was 16.9 and 24.6 per 10,000, respectively, and of permanent hypothyroidism in male and female infants 7.5 and 3.8 per 10,000, respectively.
Conclusion: A noteworthy incidence of permanent hypothyroidism in infants found in this study confirms that screening programs need to be continued in our region and that interventions to address the causes of hypothyroidism are necessary.