ABSTRACT
<p><b>OBJECTIVE</b>To study iodine nutrition of pregnant women in different occasions and thyroid function of their neonates.</p><p><b>METHODS</b>Urinary iodine of pregnant women and their serum T(3), T(4), FT(3), FT(4) were determined by chloric acid-digestion thermostatic assay and RIA, TSH determination by IRMA; neonatal umbilical cord blood TSH was determined by ELISA.</p><p><b>RESULTS</b>Median urinary iodine of pregnant women were 206.3 microg/L, 161.4 microg/L, 203.3 microg/L at 10 - 14 (first occasion), 23 - 27 (second occasion) and 39 - 40 (third occasion) week but the percentage that lower than 100 microg/L were 14.6%, 17.1%, 11.1% respectively. Serum T(3), T(4) of pregnant women was significantly higher than those women of premarital health inspection (PHIW, P < 0.001). The difference of serum T(3), T(4) of pregnant women at 10 - 14 and 39 - 40 week was not significant. Serum FT(3), FT(4) of pregnant women at 39 - 40 week were 2.61 +/- 0.47 pmol/L and 5.50 +/- 1.57 pmol/L respectively. The difference of serum TSH concentration at third occasion and first occasion of pre-pregnancy was significant but the difference of TSH frequency distribution in three groups was not significant (chi(2) = 1.138, P > 0.5). Blood TSH median neonatal umbilical cord was 1.99 mU/L but the percentage that higher than 5 mU/L was 9.4%.</p><p><b>CONCLUSION</b>For those areas with high iodized salt coverage, pregnant women had had sufficient iodine supplement and good thyroid function. The percentage of neonates from iodine sufficient pregnant women with TSH > 5 mU/L was lower than 10%. Using the normal range of nonpregnant FT(3) and FT(4) to estimate the thyroid function of pregnant women could cause mis diagnosis.</p>