Investigation of thyroid disorder in pregnancy and reference intervals in evaluation of maternal thyroid function

The importance of maternal thyroxine for the development of the fetus brain early in pregnancy has received increasing acceptance. It has more recently become evident that maternal hypothyroxinemia results in the birth of children with decreased mental and psychomotor development. In our group of 7,530 women in 9-11 week of pregnancy were determined TSH, anti TPOAb and FT4. For evaluation of results was necessary to set reference intervals for pregnant women. The TSH reference interval was determined to be 0.06 - 3.67 mU/l and for FT4 9.8 - 23.43 pmol/l was used. The limit for anti-TPO positivity was determined to be 143 kU/l. A raised concentration of TSH was found in 5.14% of women; and a suppression of TSH was found in 2.90% of women and 11.5% of pregnant women were found positive. Serum concentrations of FT4 were lower in TPOAb positive as compared to TPOAb negative women and differences of FT4 in euthyroid women with suppressed, normal and elevated TSH were found. (...) In Czech Republic, case finding screening is able to disclose only about 20% of asymptomatic mild or deep hypothyroidism or women with positive anti TPO in pregnancy. Foreign study report 70% of these high-risk pregnant women, consequently is evident need of general screening of pregnancy thyroid failure in Czech Republic. Moreover the..

Investigation of thyroid disorder in pregnancy and reference intervals in evaluation of maternal thyroid function

The importance of maternal thyroxine for the development of the fetus brain early in pregnancy has received increasing acceptance. It has more recently become evident that maternal hypothyroxinemia results in the birth of children with decreased mental and psychomotor development. In our group of 7,530 women in 9-11 week of pregnancy were determined TSH, anti TPOAb and FT4. For evaluation of results was necessary to set reference intervals for pregnant women. The TSH reference interval was determined to be 0.06 - 3.67 mU/l and for FT4 9.8 - 23.43 pmol/l was used. The limit for anti-TPO positivity was determined to be 143 kU/l. A raised concentration of TSH was found in 5.14% of women; and a suppression of TSH was found in 2.90% of women and 11.5% of pregnant women were found positive. Serum concentrations of FT4 were lower in TPOAb positive as compared to TPOAb negative women and differences of FT4 in euthyroid women with suppressed, normal and elevated TSH were found. (...) In Czech Republic, case finding screening is able to disclose only about 20% of asymptomatic mild or deep hypothyroidism or women with positive anti TPO in pregnancy. Foreign study report 70% of these high-risk pregnant women, consequently is evident need of general screening of pregnancy thyroid failure in Czech Republic. Moreover the..

Effects of latent toxoplasmosis on autoimmune thyroid diseases in pregnancy.

BACKGROUND:Toxoplasmosis, one of the most common zoonotic diseases worldwide, can induce various hormonal and behavioural alterations in infected hosts, and its most common form, latent toxoplasmosis, influences the course of pregnancy. Autoimmune thyroid diseases (AITD) belong to the well-defined risk factors for adverse pregnancy outcomes. The aim of this study was to investigate whether there is a link between latent toxoplasmosis and maternal AITD in pregnancy. METHODS:Cross-sectional study in 1248 consecutive pregnant women in the 9-12th gestational weeks. Serum thyroid-stimulating hormone (TSH), thyroperoxidase antibodies (TPOAb), and free thyroxine (FT4) were assessed by chemiluminescence; the Toxoplasma status was detected by the complement fixation test (CFT) and anti-Toxoplasma IgG enzyme-linked immunosorbent assay (ELISA). RESULTS:Overall, 22.5% of the women were positive for latent toxoplasmosis and 14.7% were screened positive for AITD. Women with latent toxoplasmosis had more often highly elevated TPOAb than the Toxoplasma-negative ones (p = 0.004), and latent toxoplasmosis was associated with decrease in serum TSH levels (p = 0.049). Moreover, we found a positive correlation between FT4 and the index of positivity for anti-Toxoplasma IgG antibodies (p = 0.033), which was even stronger in the TPOAb-positive Toxoplasma-positive women, (p = 0.014), as well as a positive correlation between FT4 and log2 CFT (p = 0.009). CONCLUSIONS:Latent toxoplasmosis was associated with a mild increase in thyroid hormone production in pregnancy. The observed Toxoplasma-associated changes in the parameters of AITD are mild and do not seem to be clinically relevant; however, they could provide new clues to the complex pathogenesis of autoimmune thyroid diseases

Relationship between free thyroxine (FT4) and positivity for <i>Toxoplasma</i> antibodies in TPOAb-positive pregnant women with latent toxoplasmosis.

<p>A: Correlation of free thyroxine (FT4) and index of positivity for anti-<i>Toxoplasma</i> IgG antibodies (IP for IgG). B: Correlation of FT4 and logarithmic values of the complement fixation test (CFT) antibodies against <i>T. gondii</i> (Spearman correlation). Dotted lines represent the reference range for FT4.</p

History of previous pregnancies and the outcome of the current pregnancy.

<p>AITD+/−: women screened positive/negative for autoimmune thyroid disease in pregnancy (TPOAb positivity and/or pathological TSH); Toxo+/−: women with/without latent toxoplasmosis. The last column shows OdsRatio reflecting increased (decreased) risk of autoimmune thyroid disease in <i>Toxoplasma</i>-infected subjects. No association was statistically significant.</p><p>History of previous pregnancies and the outcome of the current pregnancy.</p

Frequencies of pregnant women screened for autoimmune thyroid disorders according to <i>Toxoplasma</i> positivity.

<p>Toxo–: women without toxoplasmosis; Toxo+: women with latent toxoplasmosis. Positivity in screening for autoimmune thyroid disorders included either positivity of TPOAb and/or pathological TSH.</p><p>Frequencies of pregnant women screened for autoimmune thyroid disorders according to <i>Toxoplasma</i> positivity.</p

Comparison of serum TSH in pregnant women (9–12th gest. wks) with and without latent toxoplasmosis.

<p>The dotted lines represent the upper cut-off for normal values. White lines represent median values. Mann-Whitney test.</p

Association of latent toxoplasmosis and serum TPOAb levels in pregnant women (9–12th gest. wks).

<p>A: Serum TPOAb levels in <i>Toxoplasma</i>-negative vs. <i>Toxoplasma</i>-positive pregnant TPOAb-positive women. Black lines represent median values. (Mann-Whitney test). B: Negative correlation between log₂ CFT (complement fixation test) <i>T. gondii</i> antibodies and serum TPOAb levels in the TPOAb-positive pregnant women with latent toxoplasmosis (Spearman correlation).</p

Basic characteristics of women included in the study.

<p>AITD+/−: women screened positive/negative for autoimmune thyroid disease in pregnancy (TPOAb positivity and/or pathological TSH); Toxo+/−: women with/without latent toxoplasmosis. The women were included in the 9^th–12^th gestational weeks. Except of age, values are expressed as medians and range.</p><p>Basic characteristics of women included in the study.</p