Endocrine Abstracts

Introduction: The guidelines of American Thyroid Association from 2011 include age over 30 as one of the risk factors for hypothyroidism in pregnancy. The aim of our study was to verify whether age increases the risk of autoimmune thyroid diseases (AITD) in pregnant women.

Methods: We performed a cross-sectional study in 5223 unselected consecutive pregnant women in the 9th–12th gestational weeks. In a single laboratory, we measured serum concentrations of thyroid-stimulating hormone (TSH) and antibodies against thyroperoxidase (TPOAb). Reference interval for TSH was 0.06–3.67 mU/l; the upper cut-off value for TPOAb was 143 kU/l.

Results: Overall, 857 (16.4%) women were positively screened. Of these, 294 (5.63%) had TSH elevation; 146 (2.79%) TSH suppression; 561 (10.74%) were TPOAb+ and 417 (7.98%) were euthyroid and TPOAb+. The average age was 31.1 years with 65.1% of women being ≥30 years of age. Of the 294 hypothyroid women, 189 (64.3%) were ≥30 years. Using logistic regression model, we did not find any significant association between age and neither serum TSH suppression, TSH elevation and TPOAb positivity (P=0.553. P=0.680 and P=0.056, respectively), nor between age and TSH elevation with TPOAb positivity combined (P=0.967). In a subgroup analysis of risk factors for hypothyroidism in 132 hypothyroid women, addition of age ≥30 increased the proportion of women identified in a case-finding screening according to ATA from 55.3 to 85.6%.

Conclusions: Prevalence of AITD does not increase with age in pregnant women; however, addition of age ≥30 to the case-finding screening strategy may substantially improve its efficacy.

Fig 1 Absolute frequencies of 857 pregnant women positively screened for AITD according to age

Declaration of interest: The authors declare that there is no conflict of interest that could be perceived as prejudicing the impartiality of the research project.

Funding: This work was supported, however funding details are unavailable.