[Epidemiology of congenital hypothyroidism in Mexico].

OBJECTIVE

To describe the epidemiological characteristics of congenital hypothyroidism (CH) in newborns (NB) detected by the Ministry of Health of Mexico (SSA).

MATERIAL AND

METHODS

A cross-sectional study was conducted. Thyroid stimulating hormone (TSH) was quantified in 1,379,717 blood samples of NB (from umbilical cord or heel prick), collected in Guthrie cards, between January 2001 and December 2002, in medical units of the SSA. The samples with TSH > or = 15 microUI/ml for cord blood and > or = 10 microUI/ml for heel blood were considered suspicious and were submitted for confirmation by thyroid hormone profile and/or scintigraphy. When the results were positive, the case was registered as confirmed CH and the clinical and demographic data were recorded in specific formats. Statistical analysis was performed using descriptive statistics.

RESULTS

The prevalence of CH was 4.12 x 10,000 NB, with female predominance (66.84%). Regional variations in the prevalence were observed, the highest in Quintana Roo (8.13 x 10,000 NB) and the lowest in Sinaloa (0.62 x 10,000 NB). Abnormalities included 57.46% of ectopic glands, 35.91% of athyrosis, and 6.63% abnormal thyroid function conditions. The main clinical features were umbilical hernia (43.73%) and jaundice (41.58%). A total of 151 (17.12%) suspicious NB were not confirmed because of incomplete or inaccurate identification data, death of the NB, parent refusal, and change of address.

CONCLUSIONS

CH was present in 1:2,426 NB, with a female predominance (2:1); an ectopic thyroid was the most common finding, and its prominent clinical features were umbilical hernia and jaundice.