| Abstrakt: |
Physiologically, the need for thyroid hormones (TH) increases during pregnancy. This is achieved by stimulating the thyroid gland in early pregnancy with the hormone human chorionic gonadotropin (HCG) with a subsequent increase in serum free thyroxine (FT4) levels, only provided there is enough iodine for hormone synthesis. The aim is to study in a Bulgarian population of pregnant women the real status of urinary iodine concentration, thyroperoxidase antibodies (TPOAb) and thyroid hormones. Material: We studied 547 pregnant women, mean age 30±5 years. The study is cross-sectional, multicenter and population-based in 10 regions of Bulgaria (a total of 84 settlements). Methods: A morning urine sample was taken to determine urinary iodine concentration (UIC) by the inductively coupled plasma mass spectrometry (ICP-MS) method. Serum was quantified on a Cobas e601 analyzer by the ECLIA method – thyroid-stimulating hormone (TSH), FT4, TPOAb. Standard SPSS 13.0 for Windows was used in the statistical analysis. Results: The mean level of iodine in urine for the whole group of pregnant women (n=547) was 181,605±93,972 µg/L, median – 170 µg/L (95% CI: 161-177). The mean level of TSH was 2,77±1,83 mIU/L and of FT4 was 11,030±1,930 ng/L. Pregnant women with TPOAb (+) were 10,1%. TPOAb (+) pregnant women were significantly more likely to have a hypoechoic thyroid structure on ultrasound compared to TPOAb (-) pregnant women – 36% (27/75) versus 5,9% (28/472), p<0,001. Conclusion: In screening population studies, it is necessary to first clarify the level of urinary iodine concentration and only with a proven normal median urinary iodine concentration can a correct assessment of thyroid function in the same population be made. At low or high median urine iodine concentrations, a correct assessment of thyroid function in the study population cannot be made. Examination of individual urine iodine concentration is irrelevant and is denied in all current recommendations. Urine iodine concentration is determined only by population. An additional factor is the presence of TPOAb (+). [ABSTRACT FROM AUTHOR] |
