Endocrine Abstracts

Background: Etiology of infertility and miscarriages is multifactorial. Negative impact of overt thyroid dysfunction on fertility, pregnancy and development of offspring is known. Moreover, even presence of euthyroid autoimmune thyroid diseases may increase risk of miscarriages. The prevalence of positive antibodies to thyroid peroxidase (TPOAb) ranges 9–39% in women with recurrent miscarriages and 0–37% in controls. The aim of the study was to compare serum concentrations of thyroid stimulating hormone (TSH), free thyroxine (FT₄) and TPOAb between women after early miscarriages (until 16th week), women in the 1st trimester of pregnancy and controls.

Subjects and methods: One hundred and fifty randomly chosen women after at least one early miscarriage (until 16th week), 150 age-matched non-selected women in 9–11th week of pregnancy and 49 healthy non-pregnant women as controls were included in the study. All women were examined clinically and family and personal history with respect to thyroid and autoimmune diseases will be taken. Complete laboratory and ultrasound examination of thyroid gland were performed. Serum concentrations of TSH, FT₄ and TPOAb were determined by chemiluminiscence method (analyser Centaur, Bayer, Germany).

Results: Although there was not a difference between prevalence of positive TPOAb (>143 kIU/l) after miscarriages, in the 1st trimester of pregnancy and controls (9.2 vs 12.0 vs 12.2%), slightly increased serum levels of TPOAb in women after miscarriages in comparison with the 1st trimester were found (medians: 37.00 vs 26.00, P<0.001). Similarly, serum TSH was slightly higher in women after miscarriages in comparison to the 1st trimester (medians of TSH: 1.67 mIU/l vs 1.41, P=0.04). On the contrary, serum FT₄ was lower in the 1st trimester as compared with women after miscarriages (means of FT₄: 14.79±2.11 vs 13.99±1.53 pmol/l).

Conclusion: Prevalence of positive serum TPOAb did not significantly differ between women after miscarriages, in the 1st trimester of pregnancy and controls. Nevertheless, serum levels of TPOAb were slightly higher in women after miscarriages as compared to non-selected pregnant women in the 1st trimester.