Prevalence of hypothyroidism during pregnancy in a highly specialised referral centre in Mexico.

In order to determine the prevalence of overt and subclinical hypothyroidism, and isolated hypothyroxinemia during pregnancy, thyroid hormone reference values established by UMAE HGO4, IMSS in Mexico City and those suggested by the American Thyroid Association (ATA) were used. All pregnant patients, whose thyroid function was measured and whose pregnancy was monitored and resolved in UMAE HGO4, IMSS from 1 January to 31 December 2013, were included. Significant differences (p = .00419) were observed in the frequency of subclinical hypothyroidism, being higher when using ATA criteria (18.21% vs. 9.66%). The prevalence rate (UMAE HGO4 vs. ATA) for overt hypothyroidism was 1.11 vs. 1.63, for subclinical hypothyroidism 0.84 vs. 1.41 and for isolated hypothyroxinemia 3.17 vs. 2.79 per 1000 consults during the study period. Independently of prevalence rate, it is essential to provide information on the possible risks involved in pregnancy to all women of childbearing age at the time of hypothyroidism diagnosis.