Department of Health Policy, National Research Institute for Child Health and Development, Tokyo, Japan, 157-8535.
J Clin Endocrinol Metab. 2011 Dec;96(12):3846-54. doi: 10.1210/jc.2011-2180. Epub 2011 Sep 28.
Iodine deficiency in pregnant and lactating women results in serious damage to their fetuses, newborns, and weaning infants. The effect of dietary iodine intake on maternal and infantile thyroid function has not been well studied in iodine-sufficient areas, and there are few data on appropriate gestational age-specific reference ranges for urinary iodine excretion during pregnancy and lactation.
The aim of the study was to characterize the gestational change of urinary iodine excretion in Japanese women and to assess the effects of iodine status on thyroid function in mother and infant.
A total of 934 Japanese women and their 722 newborn infants were enrolled in the study. Iodine and creatinine concentrations were determined in spot urine samples in the three trimesters of pregnancy and the postpartum period at 34.0 d after delivery. Serum thyroperoxidase antibody and thyroglobulin antibody, TSH, and free T(4) were measured in each trimester, and neonatal TSH was measured on postnatal d 4.
The overall median urinary iodine concentration (UIC) during pregnancy was 219.0 μg/liter, higher than that in postpartum women (135.0 μg/liter). The prevalence of pregnant women with low UIC less than 100 μg/liter or high UIC greater than 500 μg/liter was 16.1 and 22.2%, respectively. Urinary iodine excretion decreased from 221.0 μg/liter in the first trimester to 208.0 μg/liter in the second trimester to 193.0 μg/liter in the third trimester, and then remained at 135.0 μg/liter postpartum. [corrected]. The maternal UIC correlated positively with serum TSH during pregnancy. There was no significant difference in UIC between subjects with positive thyroid autoantibodies and those with negative antibodies.
Iodine intake assessed by UIC in Japanese pregnant women is regarded as sufficient and not excessive according to World Health Organization criteria. Although the data are local, our results provide additional information on the reference range for UIC throughout gestation in iodine-sufficient areas.
孕妇和哺乳期妇女碘缺乏会对胎儿、新生儿和断奶婴儿造成严重损害。在碘充足地区，膳食碘摄入量对母婴甲状腺功能的影响尚未得到很好的研究，关于妊娠和哺乳期尿碘排泄的适当孕龄特异性参考范围的数据很少。
本研究旨在描述日本妇女尿碘排泄随妊娠的变化，并评估碘状况对母婴甲状腺功能的影响。
共纳入 934 名日本妇女及其 722 名新生儿。在妊娠的三个时期和产后 34.0 天采集尿样，测定碘和肌酐浓度。在每个孕期末期测量血清甲状腺过氧化物酶抗体和甲状腺球蛋白抗体、促甲状腺激素（TSH）和游离 T（4），新生儿在产后第 4 天测量 TSH。
妊娠期间总体中位数尿碘浓度（UIC）为 219.0μg/L，高于产后妇女（135.0μg/L）。UIC 低于 100μg/L 或高于 500μg/L 的孕妇比例分别为 16.1%和 22.2%。尿碘排泄从孕早期的 221.0μg/L 下降到孕中期的 208.0μg/L，再下降到孕晚期的 193.0μg/L，产后保持在 135.0μg/L。[校正后]。妊娠期间，母体 UIC 与血清 TSH 呈正相关。甲状腺自身抗体阳性和阴性的患者 UIC 无显著差异。
根据世界卫生组织的标准，日本孕妇 UIC 评估的碘摄入量被认为是充足的，而不是过量的。尽管这些数据是局部的，但我们的结果为碘充足地区妊娠期间 UIC 的参考范围提供了更多信息。
