Thyroid volume is associated with family history of thyroid disease in pregnant women with adequate iodine intake: a cross-sectional study in southern Brazil.
Maternal euthyroidism is important for fetal neural development. For this reason, adequate iodine nutrition during pregnancy is an important public health objective and should be periodically revised. The objective of this study was to measure urinary iodine (UI) excretion and the factors associated with thyroid volume (TV), in a group of healthy pregnant women in southern Brazil, to evaluate iodine nutrition. The median UI of the 147 women was 224 microg/l (P25=164 microg/l and P75=286 microg/l). Serum levels of free T4 and thyroglobulin did not correlate with UI, but there was a weak inverse correlation between serum TSH levels and UI (r=-0.200; p=0.02). TV, calculated through ultrasound in 57 women, was significantly associated with family history of thyroid diseases (p=0.002) and BMI (p=0.03), but there was no association with UI, corrected or not for creatinine, serum free T4, TSH or thyroglobulin, current or past smoking, gestational age, parity or oral contraceptive.


CONCLUSIONS
The healthy pregnant women studied had adequate iodine intake. In this situation, the main thyroid size determinants are probably genetic factors.
Soares
R
R
Post-Graduation Program in Medicine: Medical Sciences, Hospital de Clínicas de Porto Alegre, Federal University of Rio Grande do Sul, Porto Alegre, RS, Brazil.
Vanacor
R
R
Manica
D
D
Dorneles
L B
LB
Resende
V L
VL
Bertoluci
M C
MC
Furlanetto
T W
TW
D000328:Adult; D001938:Brazil; D003430:Cross-Sectional Studies; D004032:Diet; D005260:Female; D005865:Gestational Age; D006801:Humans; D007455:Iodine / Q000378:metabolism*; D039382:Maternal Nutritional Physiological Phenomena; D011247:Pregnancy; D013954:Thyroglobulin / Q000097:blood; D013959:Thyroid Diseases / Q000097:blood* / Q000652:urine; D013961:Thyroid Gland / Q000033:anatomy & histology* / Q000000981:diagnostic imaging; D013974:Thyroxine / Q000097:blood; D014284:Triiodothyronine / Q000097:blood; D014463:Ultrasonography; D055815:Young Adult
D014284:Triiodothyronine; D013954:Thyroglobulin; D007455:Iodine; D013974:Thyroxine
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