Reference intervals in evaluation of maternal thyroid function during the first trimester of pregnancy
Abstract
Insufficient function of the thyroid gland can cause low concentrations of thyroid gland hormones which are necessary for the proper development of the foetus brain, especially during the beginning of pregnancy. We determined the reference interval for TSH in the first trimester of pregnancy and the decision point for anti-TPO antibodies’ positivity.
We tested 5520 women from the central part of the Czech Republic during the first trimester of pregnancy for serum TSH, anti-TPO and FT4 by chemiluminometric immunoanalysis on an ADVIA Centaur system (Siemens). The reference interval for TSH was determined to be 0.06–3.67 mU/l.
The suppression of TSH was found in 2.93% of the women; a raised concentration of TSH had been found in 4.48% of the women. For anti-TPO, the cut-off was established at 143 kU/l; 11.2% of the pregnant women were found to be anti-TPO positive.