ObjectiveTo observe the thyroid status of pregnant women during the 1st and 2nd trimester of gestation,and its role in brain and neural development of their offspring's.MethodsFrom 2008 to 2009,pregnant women from nine townships of two counties in Wushi and Baicheng in Aksu prefecture of Xinjiang were selected as research subjects according to the survey standard.After informed consent signed,their urinary iodine,serum thyroid stimulating hormone(TSH) and free thyroxin(FT4) were analyzed.The value of thyroid hormone of normal pregnant women was used in diagnosis of subclinical hypothyroidism and hypothyroxinemia in pregnant women.From 2010 to 2011, The brain and neural development status among offspring born by those pregnant women were evaluated with DDST.In accordance with the results of Denver Development Screen Test (DDST) screening,pregnant women were classified into survey and control groups,and the survey group was the suspicious and abnormal of the result of DDST screening(delay),the control group was normal of the result.According to gestational age,pregnant women were divided into 4 gestation groups:G1(6 to 13 weeks),G2(14 to 18 weeks),G3 ( 19 to 23 weeks) and G4(24 to 28 weeks).ResultsA total of 396 cases of pregnant women during the 1st and 2nd trimester of gestation were investigated(survey group 102 cases,control group 294 cases).The median value of urinary iodine concentration among pregnant women in survey group was 152.4 μg/L The prevalence of subclinical hypothyroidism and hypothyroxinemia among pregnant women was 10.78％(11/102) and 3.93％(4/102),respectively.In control group,the median value of urinary iodine concentration was 180.0 μg/L The prevalence of subclinical hypothyroidism and hypothyroxinemia among pregnant women was 7.48％ (22/294) and 4.42％ (13/294),respectively.During the pregnant period from G1 to G3,the median serum TSH of pregnant women in DDST survey group (2.24,3.49,2.85 mU/L) was higher than that of DDST control group( 1.59,2.70,2.28 mU/L).Especially,the difference of TSH between the two groups during the period of G3 was statistically significant (t =4.906,P ＜ 0.05 ).ConclusionsHypothyroidism tendency of pregnant women during the period from gestation week 19th to 23rd may be an important factor in the development of brain abnormalities of their offsprings.