孕妇妊娠不同时期碘营养及甲状腺功能的动态变化研究

目的研究孕妇妊娠不同时期碘营养及甲状腺功能的动态变化情况。方法选取我院2015年3月~2016年5月接收的196例常规产前检查的妊娠期妇女,根据妊娠周期分为孕早期组(n=52,1~12周)、孕中期组(n=70,13~27周)和孕晚期组(n=74,28~40周),另选取同期63例于我院进行健康体检的女性志愿者作为对照组,对比各组间碘营养水平及FT4、TSH、FT3水平。结果孕早期组和孕中期组尿碘中位数水平均达到世界卫生组织提出的碘足量水平,孕晚期组尿碘中位数水平低于世界卫生组织提出的碘足量水平,处于碘缺乏状态。经统计学检验可知,孕早期组尿碘水平高于孕中期组和孕晚期组,差异具有统计学意义(P0.05)。孕中期组和孕晚期组尿碘水平分布情况比较差异无统计学意义(P0.05)。孕早期组碘缺乏发生率低于孕中期组和孕晚期组,差异具有统计学意义(P0.05)。孕早期组碘足量发生率高于孕中期组和孕晚期组,差异具有统计学意义(P0.05)。孕早期组FT4、FT3水平与对照组相比,差异无统计学意义(P0.05);孕中期组和孕晚期组FT4、FT3水平低于对照组,差异具有统计学意义(P0.05)。孕早期组TSH水平低于对照组,差异具有统计学意义(P0.05)。孕中期组和孕晚期组TSH水平与对照组相比,差异无统计学意义(P0.05)。随着妊娠期的延长FT4、FT3水平呈逐渐降低趋势,各组间差异具有统计学意义(P0.05),TSH水平呈逐渐上升趋势,孕中期组和孕晚期组TSH水平高于孕早期组,差异具有统计学意义(P0.05);血清FT4、TSH、FT3水平先升高后降低,再升高后趋于稳定变化。孕早期组碘营养状态与甲状腺功能指标TSH呈U形关系曲线。结论孕妇妊娠不同时期碘营养及甲状腺功能呈特异性动态变化,妊娠中晚期较易出现碘营养缺乏和甲状腺功能减退情况,妊娠期应加强对碘营养和甲状腺功能的筛查,并根据筛查结果指导妊娠期妇女合理正确补碘,避免妊娠期甲状腺相关疾病的发生。     

正常孕妇早中晚孕期的甲状腺激素参考值范围

目的 建立正常孕妇早、中、晚孕期的甲状腺激素参考值范围,为诊断、治疗、监测(或筛查)孕妇甲状腺疾病以及相关研究提供参考.方法 在碘营养充足地区一次性横断面调查孕妇及非妊娠妇女,通过统一设计的调查表和实验室检测结果严格筛选出505名不同孕期的正常孕妇和153名正常非妊娠妇女(作为对照),建立甲状腺激素参考值范围;甲状腺激素测定采用化学发光免疫测定方法,参考值范围采用中位数(P50)及双侧限值(P2.5和P97.5)表示.结果 进入本研究的所有妇女家庭均食用加碘盐,她们的尿碘中位数均达到了适宜水平,表明这些妇女不存在碘缺乏或碘过量.孕妇的TSH水平在孕早期明显低于非妊娠妇女(P<0.01),孕中期开始回升,但到孕晚期时仍未完全恢复到非妊娠水平;孕妇的FT4和FT3,随妊娠时间逐渐下降,孕中期和孕晚期均明显低于非妊娠妇女(P<0.01);孕妇的TT4和TT3自孕早期开始即明显升高(P<0.01),至孕中期达峰值,大约是非妊娠的1.5倍.结论 孕妇的甲状腺激素水平不同于非妊娠妇女,早、中、晚孕期之间也存在明显差异.因此,建立正常孕妇早、中、晚孕期的甲状腺激素参考值范围具有临床意义.     

妊娠中、晚期孕妇甲状腺功能的变化及与碘摄入量的关系

目的 了解缺碘及非缺碘地区妊娠中、晚期孕妇甲状腺功能的变化。方法 应用免疫放射分析技术，检测了90例孕妇（缺碘地区孕妇30例，非碘缺乏区健康孕妇60例）妊娠中、晚期和临床产后及30例非碘缺乏区健康非孕妇女血清TSH水平、游离T3（FT3）、游离T4（FT4）及总T4（TT4）水平。恒温消解法检测了两组孕妇临产时尿碘水平。结果 （1）妊娠中、晚期孕妇TSH水平升高，游离甲状腺激素水平下降，尤以妊娠晚期为著。（2）与正常孕妇比较，缺碘地区孕妇妊娠中期和临产后TSH水平升高，差异均有显著性（P＜0．01）；缺碘地区孕妇妊娠中，晚期和临产后FT3、FT4水平显著降低（P＜0．01）；缺碘地区孕妇临产时尿碘水平显著低于正常孕妇（P＜0．01）。结论 妊娠期孕妇表现为相对的甲状腺功能低下，以妊娠晚期为著，尤在缺碘地区。     

孕妇妊娠早期甲状腺功能及碘营养状况

目的 探讨全民食盐加碘后孕妇妊娠早期甲状腺功能及碘营养状况。方法 选择单纯食用合格碘盐补碘的60名孕妇作为研究组，于妊娠12～15周采集血、尿标本，化学发光免疫分析法测定血清FT3、FT4和TSH水平，放射免疫分析法测定血清TMAb和TGAb水平，酸消化砷铈接触分光光度法测定尿碘水平，与60名该地区非妊娠健康女性进行比较。结果 (1)研究组孕妇血清FT3、FT4水平高于对照组，血TSH水平低于对照组，差异具有显著性；(2)研究组孕妇血清TMAb和TGAb水平低于对照组，差异具有显著性；(3)研究组孕妇尿碘中位数为117．60μg／L，低于WHO推荐值。结论 全民食盐加碘后，孕妇甲状腺功能得到明显改善，但单纯食用碘盐不能满足孕妇任娠期生理需求，需要特别给予补充。     

吉林省不同孕期妇女尿碘水平与甲状腺功能关系的调查

目的为掌握全民食盐加碘后吉林省孕妇在不同孕期碘营养和甲状腺功能状况,为今后实施孕妇甲状腺功能监测的必要性和可能性提供依据。方法以省为单位,按"人口比例概率抽样方法"(PPS)抽取30个抽样单位(县)。用单纯随机抽样法从上述抽到的每个抽样单位中抽取3个乡(镇、街道办事处),每个乡(镇、街道办事处)抽取孕妇8人,每县(市、区、旗)孕妇24人。收集被调查对象尿样、血样及家中的食用盐、饮用水。采用化学发光法检测甲状腺功能(包括甲状腺抗体)指标,砷铈催化分光光度法检测尿、水碘含量,直接滴定法检测食盐碘含量。结果孕早、中、晚期妇女的尿碘中位数分别为188.6μg/L、201.9μg/L、175.7μg/L且不同孕期尿碘中位数及频数分布无显著性差异。孕早、中期妇女甲状腺功能异常主要为低FT4血症和亚临床甲状腺功能减退。孕晚期除低FT4血症和亚临床甲状腺功能减退外还有一定比例4.2%(10/240)甲状腺功能亢进(亚临床甲状腺功能亢进)存在。孕晚期妇女与孕早、中期相比甲状腺功能异常比率明显增加,孕妇抗体阳性率为10.2%(77/755)。抗体阳性者发生亚甲减3例占3.8%(3/77),低FT4血症1例占1.3%(1/77),甲亢(亚甲亢)3例占3.8%(3/77)。结论吉林省孕妇的碘营养处于适宜水平;建议在孕早期开展尿碘监测和甲功筛查。     

中国汉族碘适量地区妊娠月份特异性TSH和T4的正常参考范围

目的 建立中国碘适量地区妊娠月份特异性血清甲状腺激素的正常参考范围.方法 经过严格筛选得到碘适量地区妊娠4～36周(4周≈1个月)妇女1 118名和非妊娠妇女120名,检测血清TSH、TT4、FT4、甲状腺过氧化物酶抗体(TPOAb)以及尿碘水平.结果 妊娠期间,血清TSH在妊娠4周升高,之后开始下降,妊娠12周最低,比非妊娠时降低了35%,随后呈上升趋势,在妊娠晚期则保持稳定,与非妊娠对照组相比,TSH中位数升高了29%;血清TT4在妊娠早期迅速升高,在妊娠16周达到最高值,较非妊娠时升高70%,之后轻微下降,妊娠晚期则保持平稳,较非妊娠时升高50%;在妊娠早期,血清FT4先轻微升高,妊娠4周最高,之后逐渐下降,在妊娠中期仍然呈下降趋势,而在妊娠晚期则没有明显的变化.结论 建立妊娠月份特异性的血清TSH、TT4和FT4正常参考范围对于早期诊断妊娠亚临床甲状腺功能减退症和低T4血症是必要的.     

孕妇妊娠中晚期促甲状腺激素水平检测及其意义

目的探讨妊娠中、晚期孕妇促甲状腺激素(TSH)水平与其新生儿TSH水平之间的关系。方法应用免疫放射分析技术,检测了119例孕妇妊娠中、晚期血清的TSH水平,新生儿脐血纸片TSH水平和33例正常非孕妇组血清TSH水平。应用恒温消解尿碘测定法检测了两组孕妇临产时尿碘水平。结果①妊娠中、晚期孕妇TSH水平和新生儿TSH水平之间呈显著正相关。②孕妇妊娠中期TSH水平和新生儿TSH水平显著低于对照组(P< 0.001)。③孕妇临产时尿碘水平显著高于对照组(P< 0.01)。④两组孕妇临产时尿碘水平和TSH水平之间呈显著负相关,和新生儿TSH 水平之间呈显著负相关。结论检测妊娠中、晚期孕妇的TSH水平可评估其胎儿的碘营养状况,指导孕妇在孕期科学补碘,预防新生儿甲低的发生。     

潍坊市孕妇碘营养状况及甲状腺功能调查

目的 调查山东省潍坊市孕妇碘营养及甲状腺功能状况,为指导当地孕妇合理补碘提供科学依据.方法 收集2019年在潍坊市中医院产前检查的孕妇的尿液及空腹静脉血,分别采用贝克曼AU5800全自动生化分析仪、罗氏E601电化学发光仪及相关试剂,测定其尿碘以及游离三碘甲状腺原氨酸(FT3)、游离甲状腺素(FT4)、促甲状腺激素(TSH)3项甲状腺功能指标.结果 共调查278名孕妇,尿碘中位数184.0 μg/L,其中150 μg/L以下88人、占31.7％,150～249 μg/L 159人、占57.2％,250 μg/L及以上31人、占11.1％;不同孕期孕妇的尿碘含量差异有统计学意义(H=16.203,P＜0.05),TSH差异无统计学意义(H=1.932,P＞0.05);不同碘营养水平孕妇的TSH(H=1.498)、FT3(F=0.123)和FT4(F=0.558)差异均无统计学意义(P＞0.05).结论 潍坊市孕妇碘营养处于总体适宜水平,但仍有部分孕妇处于碘营养不足状态,尤其是孕晚期孕妇碘缺乏所占比例较高,应引起重视.     

碘适量地区妊娠妇女妊娠全程甲状腺功能动态变化研究

目的观察妊娠7周内甲状腺功能(甲功)正常妇女妊娠期间血清促甲状腺激素(TSH)和甲状腺激素的动态变化趋势及该组人群在妊娠过程中甲状腺功能减退(甲减)的发生情况。方法对2005年5月至2007年12月在沈阳地区10所医院妇产科门诊开展妊娠期甲状腺疾病的流行病学调查,239名妊娠7周(G7)内甲功正常的孕妇在G12至G36,每隔4周接受1次随访,应用固相化学发光酶免疫分析法检测血清TSH、总甲状腺素(TT4)、游离甲状腺素(FT4)、三碘甲状腺原氨酸(TT3)、游离三碘甲状腺原氨酸(FT3)、甲状腺过氧化物酶抗体(TPOAb)和甲状腺球蛋白抗体(TgAb)。按照妊娠期特异性TSH和甲状腺激素的参考范围计算甲减的发生率。结果血清TSH在G12降至最低点(与其他各时点比较,P均0.01),之后逐渐回升。血清TT4在G12时升至高峰144.14nmol/L(G12对G6,P0.01),之后维持在较高水平,均较基础水平明显升高(与G6比较,P均0.01)。血清FT4自妊娠早期开始下降,至末期较平稳。血清TT3和FT3在G16前逐渐升高,之后稳定在高水平。6.7%基础甲功正常的孕妇在G12以后发生亚临床甲减,其基础TSH明显高于甲功持续正常的孕妇(P0.01)。81.25%(13/16)的亚临床甲减发生在妊娠前半期。基础血清TSH2.5mIU/L的孕妇在妊娠过程中发生亚临床甲减的比率为17.5%(14/80),明显高于基础血清TSH≤2.5mIU/L孕妇的发生率(P0.01)。结论妊娠期间血清TSH和甲状腺激素随妊娠进展而变化;基础血清TSH2.5mIU/L的孕妇在妊娠前半期更容易发生亚临床甲减。     

高水碘地区甲状腺抗体阴性妊娠期妇女甲状腺功能分析

目的 探讨高水碘地区甲状腺抗体阴性妇女妊娠各期甲状腺功能的变化特征.方法 在高水碘地区选天津市静海县妇幼保健院(饮水水碘>200μg/L)和在适碘地区选天津市和平区妇幼保健院(饮水水碘<10μg/L,碘盐普及率>90%,居民尿碘中位数>100μg/L)作为调查地点.在妇幼保健院门诊,选取妊娠资料完整的妊娠早、中、晚期孕妇各50名,采集血样,用化学发光法检测甲状腺功能.同时收集日间随意一次尿样、家中饮用水样和食用盐样,尿碘测定采用砷铈催化分光光度法,水碘测定采用快速定量检测试剂盒,盐碘测定采用硫代硫酸钠滴定法.结果 ①甲状腺抗体阴性孕妇中,高水碘地区孕早期妇女血清TT_4、TT_3、FT_4明显低于适碘地区(111.97 nmol/L vs 140.46 nmol/L,Z=3.56,P<0.01;1.86 nmol/L vs 2.26 nmol/L,Z=2.35,P<0.05;14.13 pmol/L vs 16.32 pmol/L,Z=5.14,P<0.01);孕中期妇女血清FT_4、FT_3明显低于适碘地区(11.98 pmol/L vs 14.30 pmol/L,Z=5.75,P<0.01;4.04 pmol/L vs 4.32 pmol/L,Z=2.76,P<0.01);孕晚期妇女血清,TT_3、TSH明显高于适碘地区(2.88 nmol/L vs 2.70 nmol/L,Z=-2.27,P<0.05;2.37 mU/L vs 1.75mU/L,Z=-2.70,P<0.01).②高水碘地区孕妇家中饮水碘和孕妇尿碘明显高于适碘地区(205.57μg/L vs8.22μg/L,Z=-14.71,P<0.01;305.91μg/L vs 191.86μg/L,Z=-4.01,P<0.01),家中盐碘明显低于适碘地区(26.5 mg/kg vs 31.7 mg/kg,Z=5.68,P<0.01).③健康且没有甲状腺病史的被调查孕妇中,妊娠各期甲状腺抗体阳性率在高水碘和适碘地区之间比较差异无统计学意义(孕早期:10.20%vs 10.64%;孕中期:14.00%vs9.52%;孕晚期:4.00%vs 7.69%,P均>0.05).结论 高水碘地区甲状腺抗体阴性孕妇妊娠各期甲状腺功能不同于适碘地区,对高水碘地区孕妇应加强孕期(特别是孕早、中期)甲状腺功能监测.     

我国四地区正常孕妇的尿碘水平分析

目的 以世界卫生组织(WHO)推荐的标准作依据,分析我国正常孕妇的尿碘水平,推荐作为评价孕妇人群碘营养状况的参考值,用于孕期碘营养监测及其相关研究.方法 在横断面调查中选择健康、碘营养充足、甲状腺功能正常、甲状腺自身抗体阴性的604名孕妇和192名当地非妊娠妇女作为本次研究对象,采用标准方法检测饮水、食盐、尿液的碘含量,采用化学发光免疫测定方法检测血清TSH、FT4、FT3、甲状腺过氧化物酶抗体(TPOAb)、甲状腺球蛋白抗体(TgAb).结果 (1)平均饮水碘含量为3.0μg/L,提示饮水提供的碘量很低.(2)平均食盐碘含量为31.7mg/kg,推测每日至少从食盐中获得240μg碘(按每人每日摄盐10 g计算,再减去烹饪过程可能丢失20%碘量),足以满足孕妇对碘的需求量.(3)604名孕妇的尿碘中位数为173.1μg/L,早、中、晚孕期分别为174.5、167.0和180.7μg/L,均达到了WHO推荐的150～249μg/L适宜水平,但未超过200μg/L.非妊娠妇女尿碘中位数为240.2μg/L,达到了WHO推荐的成人200-299 μg/L"超需要量"水平.(4)这些妇女都是甲状腺功能正常及抗体阴性者,但孕期TSH水平明显低于非妊娠妇女,以孕早期为最低;FT4及FT3,也低于非妊娠妇女,并随孕期进展而逐渐降低.结论 WHO推荐的孕妇适宜尿碘中位数水平(150-249μg/L)适用于我国孕期妇女,但我国孕妇尿碘偏低,位于150-200μg/L之间;同地区的非妊娠妇女尿碘水平偏高,建议市场可以供应不同浓度碘盐以满足不同人群的需求.

Abstract：

Objective To analyze the median urinary iodine(MUI)level in normal pregnant women based on World HeMth Organization(WHO) recommended criterion,and to provide the MUI reference values for monitoring and evaluating iodine nutrition during pregnancy and related studies.Methods Total 604 normal pregnant and 192 non-pregnant women(as a comparison)were selected from a cross-sectional survey.These women were all healthy,iodine sufficient,with normal thyroid function,and negative anti-thyroid antibodies.The iodine content in drinking water,edible salt,and urine was determined by standard methods,and serum TSH,FT4,FT3,thyroid peroxidaseantibody(TPOAb),and thyroglobulin antibody(TgAb)were measured using chemiluminescent immunoassay.Resuits (1)The iodine in drinking water was 3.0μg/L indicating such small amount of iodine could be neglected for daily iodine intake.(2)All women consumed iodized salt with the median iodine in salt of 31.7 mg/kg.The daily iodine intake of at least 240 μg could be roughly estimated if an average of 10 g salt was taken per person per day and further subtracted by 20%iodine lost during cooking,which could meet the iodine needs during pregnancy.(3)The MUI of 173.1μg/L was calculated from 604 pregnant women having 174.5,167.0,and 180.7 μg/L during the first,second,and third trimesters,respectively,reaching the optimal level of 150-249 μg/L recommended by WHO for pregnant women.However,our data showed relatively lower levels,not reaching 200μg/L.The MUI of 240.2μg/L was calculated from 192 non-pregnant women,reaching the level of"above requirement"(200-299μg/L) recommended by WHO for adults.(4)All women were euthyroid and antibody-negative,but the TSH level in pregnant women was lower than that in non-pregnant women,in particular during the first trimester,while FT4 and FT3 were considerably decreased compared with the non-pregnant(with an exception of FT4 in the first trimester),and both gradually declined with the gestational age.Conclusions The optimal MUI level of 150-249 μg/,L recommended by WHO can be applied to pregnant Chinese women,but our data provided a relatively low range of 150-200μ/L throughout pregnancy.The higher MUI of 240.2μg/L in non-pregnant women indicated that iodized salt with different contents should be supplied on market to meet the requirement of different groups of population.     

上海市浦东新区周浦和康桥地区孕妇碘营养状况及新生儿足跟血促甲状腺激素水平分析

目的 调查上海市浦东新区周浦和康桥地区(简称周康地区)孕妇的碘营养状况,新生儿足跟血促甲状腺激素(TSH)水平及其与母体孕期尿碘水平之间的关系.方法 于2009年4月至2010年11月,选择上海市周康地区孕早、中、晚期妇女各200例,哺乳期妇女193例,生育期非孕妇女(简称育龄期妇女)200例,同期新生儿200例作为观察对象.采集各期妇女随意1次尿样,用砷铈催化法检测尿碘,同时采集新生儿出生后72 h的足跟血,用时间分辨荧光免疫法(TRFIA)测定TSH.结果 600例孕妇的尿碘中位数为161.35 μg/L,其中孕晚期妇女尿碘中位数(126.35 μg/L)明显低于孕早、中期,哺乳期及育龄期妇女(178.80、180.50、167.90、163.40μg/L,P均＜0.05);孕晚期妇女尿碘＜150 μg/L的比例[57.5％(115/200)]明显高于孕早、中期,哺乳期,育龄期妇女[39.0％(78/200)、39.5％(79/200)、16.6％(32/193)、23.0％(46/200),P均＜0.05].孕早、中、晚期妇女尿碘≥300 μg/L的比例[9.0％(18/200)、8.0％(16/200)、5.0％ (10/200)]明显低于哺乳期、育龄期妇女[20.2％(39/193)、20.5％(41/200),P均＜0.05].200例新生儿足跟血TSH水平为(2.92±1.83)mU/L,范围为0.01～9.76 mU/L,TSH＞5 mU/L的比例为11.0％(22/200),超过世界卫生组织(WHO)碘营养适宜标准(＜3％).结论 上海市浦东新区周康地区孕妇总体碘营养水平处在适宜范围,但孕晚期妇女存在轻度碘营养不足,而该区新生儿有碘营养缺乏的可能.应加强对孕妇碘营养的监测,科学补碘.     

Trimester- and method-specific reference intervals for thyroid tests in pregnant Chinese women: methodology, euthyroid definition and iodine status can influence the setting of reference intervals

Objective The importance of diagnosis and treatment of thyroid dysfunction during pregnancy has been widely recognized. We therefore established trimester‐ and method‐specific reference intervals for thyroid testing in pregnant women according to the NACB recommended criteria. Several factors can affect the setting of reference intervals, in particular manufacturer’s methodology, euthyroid definition and iodine status. Design Cross‐sectional dataset analysis. Subjects Five hundred and five normal pregnant women at different stages of gestation were rigorously selected for setting reference intervals. All were healthy, iodine sufficient, euthyroid and negative for both serum thyroid peroxidase antibody (TPOAb) and thyroglobulin antibody (TgAb). Measurements Thyrotrophin (TSH), total and free thyroxine (TT4 and FT4), total and free triiodothyronine (TT3 and FT3) and anti‐TPOAb and anti‐TgAb were measured using the Bayer ADVIA Centaur system. Iodine content in drinking water, salt and urine was determined by national standard methods. The 2·5th and 97·5th percentiles were calculated as the reference intervals for thyroid hormone levels during each trimester. Results All participants had long‐term consumption of iodized salt and median urinary iodine of 150–200 μg/l during each three trimester. The reference intervals for the first, second and third trimesters were, respectively, TSH 0·03–4·51, 0·05–4·50 and 0·47–4·54 mIU/l and FT4 11·8–21·0, 10·6–17·6 and 9·2–16·7 pmol/l. The manufacturer’s method, euthyroid definition and iodine status may influence TSH and FT4 reference intervals. Alterations in thyroid hormone concentrations during pregnancy differed at different stage of gestation and to those of a nonpregnant state. Conclusions The trimester‐ and method‐based reference intervals for thyroid tests during pregnancy are clinically appropriate. Some variables should be controlled when establishing reference intervals.     

Iodine deficiency disorder among pregnant women in a tertiary care hospital of Kolkata, India

The present unicentric, hospital based, non-interventional, cross-sectional study was undertaken to assess the iodine status of pregnant women attending the antenatal clinic at a medical college in Kolkata, India, during the different trimesters of pregnancy and to compare their iodine status with those of age-matched non-pregnant control women. Assessment of the iodine status was based on urinary iodine excretion (UIE). Serum levels of free triiodithyronine (fT3), free thyroxine (fT4) and thyroid stimulating hormone (TSH) were assayed as an indirect measure of iodine status. A statistical comparison between the median values for UIE, TSH, fT4 and fT3 in pregnant women and non-pregnant controls revealed a significant difference between the median values for UIE (p < 0.0047), TSH (p < 0.00001) and fT4 (p < 0.001). UIE and fT4 were significantly lower and TSH was significantly higher in pregnant women than in non-pregnant controls. However, no significant difference in median values for fT3 concentration between the groups was seen (p = 0.4). Only 4 cases out of 200 pregnant women had an UIE of less than the lower cut-off value for UIE recommended by the WHO corresponding to optimal iodine intake. The results indicate most pregnant subjects attending the antenatal clinic at Medical College Kolkata, India, a tertiary care institution, did not suffer from significant iodine depletion. This may be ascribed to increased awareness of this condition and the accessibility of iodized salt among the study population.     

Longitudinal study of pituitary-thyroid axis in pregnancy

The thyroid undergoes important changes during pregnancy. In order to evaluate changes of the hypophyseal-thyroid axis during this period we studied the thyroid function in 587 pregnants by determining serum TSH, free T4, TPO antibodies and betahCG in the 1st trimester and serum TSH, free T4 and TPOAb in to 2nd and 3rd. We observed a progressive rise in average serum TSH in the 2nd (2.14 mU/L) and 3rd (2.96 mU/L) trimesters when compared to the 1st (1.39 mU/L). Serum TSH values in the 1st trimester were inversely correlated with betahCG levels in as much as TSH levels below 0.4 mU/L corresponded to average betahCG levels of 129,000 UI/L whereas these were 34,200 UI/L in the normal TSH group. A slight decrease in free T4 levels was also observed in the 2nd and 3rd trimesters (averages 1st: 1.15; 2nd: 0.99; 3rd: 0.94 ng/dl). Thyroid autoimmunity defined as positive TPOAb occurred in 13.9% of our patients during pregnancy. No significant differences in TSH and free T4 medium values were found between patients with positive TPOAb and those without. However, a significantly higher proportion of pregnants had abnormal hormonal values throughout the trimesters. We conclude that thyroid function is affected by pregnancy with a tendency for decline as it progresses, a feature more easily observed in positive TPOAb group.     

Autoimmune thyroid disease in the puerperium. Predictive value of thyroid enlargement and related hormonal changes occurring during pregnancy

The incidence of goiter detected during pregnancy and its significance as an indicator of autoimmune thyroid disease after delivery was investigated in a sample of 707 pregnant women (81% in their 2nd trimester of gestation). Goiter was detected in 106 subjects (15%). Blood T4, T3, TSH, free T4 index (FT4I), antimicrosomal antibodies (AMA) and urinary iodine excretion were measured in these women and in a control group of gravidas without goiter. These measurements were repeated at 1 and 3 months after delivery. Compared with controls during pregnancy, subjects with goiter had lower FT4I values (11.0 +/- 2.8 vs 9.0 +/- 1.8; p less than 0.01) and higher TSH values (2.9 +/- 0.6 microU/ml vs 4.2 +/- 2.1 microU/ml; p less than 0.01). In contrast, T4, T3, AMA and urinary iodine excretion values were similar in both groups. In subjects with goiter FT4I values increased over pregnancy levels at 1 month (11.2 +/- 2.0; p less than 0.05) and 3 months (14.0 +/- 3.0; p less than 0.05) after delivery; in 29% a biochemical hyperthyroidism (FT4I greater than 13.5) was detected. During the same period TSH values decreased significantly (1 month: 1.9 +/- 0.7 microU/ml; p less than 0.05; 3 months: 2.7 +/- 3.0 microU/ml; p less than 0.05). Frequency of positive AMA increased from 8.6% during pregnancy up to 32.1% in the post-delivery period (p less than 0.01). In the control group no variation in the FT4I, TSH or AMA were observed after delivery. These results indicate that goiter during pregnancy is common in Chilean gravidas and that it has predictive value for the appearance of autoimmune thyroid disease after delivery.     

Goitrogenesis during pregnancy and neonatal hypothyroxinaemia in a borderline iodine sufficient area

OBJECTIVE: Severe iodine deficiency disorders (IDDs) may have been eradicated in many parts of the world, but milder forms still exist and may escape detection. We evaluated the impact of pregnancy on the maternal and fetal thyroid axis in Hong Kong, a coastal city in southern China with borderline iodine intake. DESIGN: A prospective study performed in a maternity hospital. PATIENTS: Two hundred and thirty pregnant women were prospectively studied and their neonates assessed at birth. MEASUREMENTS: Urine iodine concentration, thyroid function tests and thyroid volume (TV) by ultrasound were determined in the mothers during pregnancy and up to 3 months postpartum and in the neonates. RESULTS: Increased urinary iodine concentration was seen from first trimester onwards and the proportion of women having urine iodine concentration of < 0.4 micromol/l decreased from 11.3% in the first trimester to 4.7% in the third trimester. There was progressive reduction in circulating fT4 and fT3 concentrations and free thyroxine index (FTI) with increasing gestation and the percentage of women having subnormal levels at term were 53.2%, 61.1% and 4.8%, respectively. The serum TSH concentration during pregnancy doubled towards term. In the first trimester, multiparous women had significantly larger TV than the nulliparous women (P < 0.001). By the third trimester, TV had increased by 30% (range 3-230%) so that the goitre incidence was 14.1%, 21.8%, 25.9% during the three trimesters of pregnancy, and 24.3% and 21.9% at 6 weeks and 3 months postpartum (ANOVA, P < 0.05). The change in thyroid volume during pregnancy correlated positively with the change in thyroglobulin (r = 0.225, P < 0.002) and negatively with urinary iodine concentration (r = - 0.149, P < 0.02). Fourteen women with excessive thyroidal stimulation in the second trimester (defined as those with thyroglobulin (Tg) concentrations in the highest tertile and FTI in the lowest tertile) were found to have lower urine iodine concentrations and larger TV (both P < 0.005) throughout pregnancy, and their neonates had higher cord TSH (P < 0.05), Tg (P < 0.05) and slightly larger TV (P = 0.06) as compared to the findings in 216 pregnant women without evidence of thyroid stimulation. Seven neonates (50%) born to these women had subnormal fT4 levels at birth. CONCLUSION: In a borderline iodine sufficient area, pregnancy posed an important stress resulting in higher rates of maternal goitrogenesis as well as neonatal hypothyroxinaemia and hyperthyro- trophinaemia. An adequate iodization program is necessary to eliminate iodine deficiency disorders during pregnancy.