Relatively high rate of postpartum thyroiditis in the Straits of Messina area. Predictivity of both postpartum thyroiditis and permanent hypothyroidism by performing, in the first trimester of gestation, thyroid ultrasonography and measurement of serum thyroperoxidase and thyroglobulin autoantibodies.

The prevalence of postpartum thyroiditis (PPT) averages 5%, with a range from 1% (Thailand) to 22% (Wales, UK, and Liguria, Italy), but 3.6% in another Italian region (Puglia). Evolution of PPT into permanent hypothyroidism (PH) occurs in approximately 50% of cases. Positive thyroperoxidase autoantibodies (TPOAb) in a pregnant woman is a strong predictor of PPT. Because in previous gestational cohorts we found an approximate 12% rate of TPOAb positivity, which compares with 15% in the Liguria cohort and 6% in the Puglia cohort, we hypothesized that the currently unknown prevalence of PPT in Sicily would approximate the said Liguria prevalence. We also explored the predictive value of serum thyroglobulin Ab (TgAb) positivity and ultrasonographic signs suggestive of thyroiditis (UST) at first trimester of gestation for PPT. Of 412 pregnant women who were followed-up for 1 year after delivery, 63 (15.3%) developed PPT, and 54% of them had PH. Gestational rates of TPOAb positivity alone, TgAb positivity alone or UST were 11.4%, 7.8% or 35.0%, with associated PPT rates of 66%, 45% or 36%. TgAb assay allowed detection of 9/63 PPT women (14.3%) who were TPOAb-negative. However, TPOAb remained a better predictor compared to TgAb or UST (odds ratio = 32