Abstract: Objective To examine the iodine status of pregnant women and thyroid function of neonate in an iodinesufficient area.Methods Totally 174 pregnant women in the third trimester of pregnancy were chosen from Tianjin Central Gynecological and Obstetrical Hospital.Then the limosis morning-urine of pregnant women and neonates cord blood were collected.The urinary iodine level was determined with arsenic-cerium catalytic contact.The levels of free triiodothyronine(FT₃),free thyroxine(FT₄),and sensitive thyroid-stimulating hormone(sTSH) in serum were measured with chemiluminescence.Results The median of urinary iodine of the women was 217.06 μg/L.Most of the women(63.2%) were adequate for iodine nutrition,but some of them were in the status of iodine deficiency(27.6%) and iodine excess(9.2%).The average level of FT₃,FT₄ and sTSH was 2.31±0.28 pmol/L,16.50±1.35 pmol/L,and 4.71(3.96-6.04) μU/mL,respectively.There was no correlation between urinary iodine and FT₃ among the women and FT₄ and sTSH levels among the neonate(P > 0.05).No statistic significance was found in neonates' FT₃ and FT₄ level with their mothers in different iodine nutrition status.The sTSH level of the neonates with the mothers in iodine-sufficient status was higher than that with the mothers in iodine more than adequate requirement status.The level of sTSH of baby boys was higher than that of baby girls,and baby boys' sTSH tended to distribute with higher values.The sTSH level of neonates produced by transvaginal was higher than that of produced by cesarean section.Conclusion The iodine status of the most pregnant women in iodine-sufficient area was adequate,but there were still some iodine deficiency and iodine excess individuals.Neonates with mothers of insufficient iodine nutrition were more likely to have hypothyroidism and subclinical hypothyroidism.Gender and way of parturition may affect the level of sTSH in neonates.