Pol. Merkur. Lek (Pol. Med. J.), 2013, XXXIV/202: 200-204 Maximize

Pol. Merkur. Lek (Pol. Med. J.), 2013, XXXIV/202: 200-204

Title: Iodine supply and thyroid function in the group of healthy pregnant women living in Warsaw

Authors: Krasnodębska-Kiljańska M., Kondracka A., Bartoszewicz Z., Niedźwiedzka B., Ołtarzewski M., Grzesiuk W.,
Bednarczuk T., Bar-Andziak E.

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Iodine supply and thyroid function in the group of healthy pregnant women living in Warsaw

Krasnodębska-Kiljańska M.1, Kondracka A.1, Bartoszewicz Z.1,2, Niedźwiedzka B.3, Ołtarzewski M.4, Grzesiuk W.1, Bednarczuk T.1,2, Bar-Andziak E.1

1Chair and Department of Internal Medicine and Endocrinology, Warsaw Medical University; 2Endocrinology Unit, Department of Human Epigenetics, Mossakowski Medical Research Centre, Polish Academy of Sciences; 3Department of Gynaecology and Oncological Gynaecology, Military Institute of Medicine; 4Institute of Mother and Children, Department of Screening Evaluation

Iodine deficiency and thyroid gland disorders are especially harmful for pregnant women and normal fetal development. After initiation in 1997of obligatory iodine prophylaxis, Poland has been found since 2003 a country with sufficient delivery of this microelement. However, in the population of pregnant women, slight deficiency of this element still exists. Insufficient iodine supply results in abnormalities of thyroid hormones’ biosynthesis. Simultaneously, adaptive changes, occurring in pregnancy, make the proper interpretation of hormone’s assays difficult. Lack of normative data for the thyroid hormones concentration in the each pregnancy trimester for Polish population cause additional difficulties in the interpretation of these results.
The aim of the study
was prospective observation of iodine intake and thyroid function in healthy pregnant women supplemented with 150 μg of iodine daily
Materials and methods
. 62 healthy pregnant women living in Warsaw in the early weeks of pregnancy, confirmed by ultrasonographic examination, were included to this study. Pregnancies were singleton resulting in birth of healthy neonates. Urinary iodine concentrations (UIC), serum TSH, fT4, fT3, antyTPO, thyroid volume and morphology by the ultrasonography examination were assessed in consecutive trimesters of pregnancy. TSH level was measured in the each newborn.
. Low urinary iodine concentrations (UIC)-median 96 μg/l was found at the beginning of pregnancy. Only in 14% of pregnant women UIC exceeded 150 μg/l. In spite of intended supplementation of at least 150 μg of extra iodine per day, medians of UIC in the next trimesters were 122 μg/l and 129 μg/l, respectively. TSH levels kept reference values for the 1st trimester of pregnancy in 86% of participants and in the next trimesters in 85% and 95%, respectively. Levels of fT4 were within reference range for the women in the 1st trimester. In 2 nd trimester 12% and in 3rd trimester 33% of pregnant women had fT4 level below the reference value. Concentrations of fT3 were within reference values during whole pregnancy. Median thyroid volume was respectively 11.12 ml; 13.0 ml and 15.75 ml (range: 6.8–26.8 ml) in subsequent trimesters .Median neonatal' TSH level on the 3rd day of life, as a screening of thyroid insufficiency, was 1.34 mIU/l (range: 0.01–6.6 mIU/l) and in 4. 41 % of newborns TSH concentrations were higher than 5 mIU/l.
. Despite the sufficient supply of iodine in the whole population, iodine consumption among the pregnant women is still częstonot satisfactory. The increase of TSH values above the upper reference level for pregnant women in 15% of patients may be related to iodine deficiency.It is important to educate pregnancy planning women about this problem. Our observations confirm the importance of the recommendations that during the pregnancy every woman should receive supplementation of iodine at the minimal amount of 150 μg daily.

Key words: pregnancy, iodine, thyroid

Pol. Merk. Lek., 2013, XXXIV, 202, 200