The safest and most efficient way to diagnose congenital hypothyroidism (CH) is through screening programs using serum thyroid stimulating hormone (TSH). CH occurs in one in 1:2,300 - 1:5,000 births but higher rates are found in iodine-deficient areas. Iodine was measured in the urine of 141 newborns (87 males and 54 females) from Ribeirão Preto to complement the screening program developed by the School of Medicine of Ribeirão Preto (FMRP-USP) and Federal University of São Paulo (UNIFESP). TSH values did not disclose any case of CH, although we have seen an elevated ratio (0.96%) of calls for retests. The iodine urinary levels ranged from 2.1 to 194µg/l (mean 58.3±36.2µg/l). No differences between the levels of urinary iodine and gender or gestational ages were observed. A negative correlation between urinary iodine and TSH of blood from umbilical cord was found (r= -0.20, p= 0.02).
Urinary iodine; Congenital hypothyroidism; Transitory hyperthyrotropinemia; TSH of umbilical cord
