| Abstract:
Introduction: Following screening of newborns for congenital hypothyroidism (CH) in Tehran for
49 months and in Damavand for 21 months, a question was raised as to whether there are any
differences between the recall rates and CH incidences in metropolitan and district populations.
The present study was conducted to address the aforementioned issue. Material and Methods:
From February 1998 to March 2002, cord blood spot samples from 8 hospitals and a rural birth
center in Tehran (the capital) and Damavand (district) were collected and tested for TSH
measurement using a two site IRMA method. TSH values ~ 20 mUll were recalled. The diagnosis of
CH was confirmed using age-adjusted reference values for serum TSH and T4 levels. The
frequency distribution of recalls and CH cases in Tehran and Damavand were compared using X2
and Fisher(s) exact tests, respectively. Results: Of 30085 (Tehran: 28001 and Damavand: 2084)
screened neonates, 319 (Tehran: 297 and Damavand: 22) had cord TSH values ≥20 mU/L. The
recall rate was 1.06% (Tehran: 1.06% and Damavand: 1.06%). Thirty.two (Tehran: 30 and Damavand:
2) neonates had CH. The CH incidence was 1 in every 940,933, and 1042 live births in total, Tehran,
and Damavand populations, respectively. A total of 5119 out of 18260 (28%) neonates had parental
consanguinity. This was 4582 out of 16178 (28.3%) in Tehran and 537 out of 2082 (25.8%) in
Damavand. The recall rates and CH incidences were not significantly different in Tehran and
Damavand. conclusion: Preliminary findings of CH screening program showed that recall and CH
occurrence do not have significantly different distributions in Tehran and Damavand and CH was
prevalent in both regions. It could be concluded that CH might be prevalent in other parts of the
country.
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