妊娠期碘营养状况及其与甲状腺功能关系研究

目的探讨广州地区孕妇碘营养状况及其与甲状腺功能的关系。方法选择2012年3月至2014年2月在中山大学孙逸仙纪念医院产检的孕妇815为研究对象,进行甲状腺功能、抗甲状腺过氧化物酶抗体(TPO-Ab)和尿碘的检测,结果异常者定期复查,密切监测母胎情况,追踪至妊娠终止。结果 815例无甲状腺疾病史孕妇尿碘中位数(median urinary iodine,MUI)为197.0μg/L;其中碘缺乏者39.6%(323/815);碘适宜者20.9%(170/815);碘超足量者27.4%(223/815);碘过量者12.1%(99/815)。早中晚孕期MUI分别为208、182.5、174.5μg/L。不同碘营养状况下甲状腺功能、甲状腺疾病的患病率及TPO-Ab阳性率的差异无统计学意义,均P0.05。结论孕妇碘营养状态为碘适宜,但个体间差异较大。不同碘营养状况下甲状腺疾病的患病率无明显差异,即轻度碘缺乏或碘过量不增加甲状腺疾病的患病率。随着孕周的增加,尿碘值逐渐下降,但都在碘适宜的范围内。     

妊娠晚期妇女甲状腺疾病特点及甲状腺自身抗体变化的研究

目的 探讨妊娠晚期妇女甲状腺疾病的患病率、患病特点和甲状腺自身抗体的变化.方法 选择664例妊娠晚期妇女为妊娠组,276例非妊娠育龄妇女作为对照组.应用固相化学发光酶免疫法测定两组妇女的血清促甲状腺激素（TSH）和抗甲状腺过氧化物酶抗体（TPOAb）水平;TSH水平检测异常者加测游离甲状腺素（FT4）和游离三碘甲状腺原氨酸（FT3）,同时测定尿碘水平.按如下标准确定诊断：TSH＜0.3 mU/L,FT4和（或）FT3水平升高者诊断为临床甲状腺功能亢进症（甲亢）;TSH＜0.3 mU/L,而FT4和FT3水平正常者诊断为亚临床甲亢;TSH＞4.8 mU/L,FT4水平降低者诊断为临床甲状腺功能减退症（甲减）;TSH＞4.8 mU/L,而FT4和FT3水平正常者诊断为亚临床甲减.TPOAb＞5 kU/L为阳性.结果 （1）妊娠组妇女尿碘平均水平为201.5μg/L,对照组妇女尿碘平均水平为196.0μg/L,均为碘充足水平.两组比较,差异无统计学意义（P＞0.05）.（2）妊娠组妇女甲状腺疾病总患病率为7.8%（52/664）,对照组妇女甲状腺疾病总患病率为6.9%（19/276）.两组比较,差异无统计学意义（P＞0.05）.（3）两组妇女的甲状腺患病类型有明显不同,妊娠组妇女甲亢患病率为1.1%（7/664）,甲减患病率为6.8%（45/664）,妊娠组妇女甲亢患病率明显低于甲减,两者比较,差异有统计学意义（P＜0.01）;对照组甲亢患病率为4.7%（13/276）,甲减患病率为2.2%（6/276）,两者比较,差异无统计学意义（P＞0.05）.妊娠组与对照组妇女的甲亢或甲减患病率分别比较,差异均有统计学意义（P＜0.01）.（4）妊娠组非患病妇女的TSH水平显著高于对照组,分别为2.50 mU/L及1.54 mU/L,差异有统计学意义（P＜0.01）;妊娠组妇女TPOAb阳性率显著低于对照组,分别为3.3%（22/664）及9.4%（26/276）,差异有统计学意义（P＜0.01）.结论 妊娠晚期妇女甲状腺疾病的特点是甲减的患病率高,同时甲状腺自身免疫功能受到抑制.     

孕妇尿碘及甲状腺功能监测

目的　探讨不同孕周、不同碘营养状况下孕妇尿碘水平及孕妇、新生儿甲状腺功能 ,分析孕妇碘营养状况及药物治疗的必要性。方法　于 1997年 7月～ 2 0 0 3年 3月期间 ,收集在我院就诊及分娩的孕产妇尿标本 185 2 8例次 ,按照是否补充“金典”分为A组 (未补碘 )及B组 (补碘 ) ,按照孕周分为 :孕早期 1组 ,孕中期 2组 ,孕晚期 3组 ;另随机抽取 2 4 6例孕产妇 ,并分组 :早孕未补充“金典”者 81例为JA1组 ,孕足月未补充“金典”者 86例为JA3组 ,孕足月补充“金典”者 79例为JB3组 ,对该组孕妇其及分娩的新生儿脐带血进行甲状腺功能的检测。结果　①本组孕产妇尿碘中位数为 2 31μg L ,尿碘值 <5 0 μg L、 <10 0 μg L、 <2 0 0 μg L的发生率分别为 2 4 %、 13 9%及 4 3 4 % ;②孕早、中、晚期未补充“金典” (及补充“金典”)组尿碘值中位数分别为 :16 2 μg L (377μg L)、 193μg L (2 86 μg L)、 2 6 0 μg L (382 μg L) ,前者尿碘值均低于后者 ,其差异有显著性 (P =0 0 0 0 ) ;随着孕周的增加 ,未补充“金典”组尿碘值依次升高 ,差异有显著性 (P =0 0 0 0 ) ;③三组孕妇甲状腺功能检测值的中位数均在正常范围内 ,除TG一项外 ,FT3、FT4 、TSH、TM等几项差异均有统计学意义(P =0 0 0 0 ) ;④足月     

我国部分地区孕妇和哺乳妇女适宜的尿碘参考值范围的制定

目的:对我国部分地区正常孕妇和哺乳妇女的尿碘值进行测定,以期对尿碘值范围提供一定的参考.方法:收集我国6个地区孕妇和哺乳妇女的尿碘和甲状腺功能数据,对甲状腺功能正常的141例孕妇和170例哺乳妇女的尿碘值进行统计分析.结果:我国部分地区孕妇和哺乳妇女适宜的尿碘值范围分别为90～500 μg/L和70～450μg/L.结论:本研究为孕妇和哺乳妇女碘营养状况的个体诊断提供了一种思考方法.     

产后甲状腺炎

产后甲状腺炎 (post partumthyroiditis,PPT)是在产后 1年内发生的甲状腺功能障碍综合征[1 ,2 ] 。 1 948年 ,Roberton首次描述了与产后有关的甲状腺功能减退的症状 ,直到 2 0世纪 70年代 ,相继发表了来自日本、加拿大等国家关于PPT的系列研究报告 ,再次证明了PPT的存在 ,并使人们对其免疫学特征有了新的认识[1 ] 。一、发生率PPT是产后妇女的一种常见病[1 ] 。多数研究报道 ,PPT在产后妇女中的发病率是 5 %～ 9% [1 ,3,4 ] 。由于随访例数及所用方法不同 ,各文献报道发病率也有所不同 (3 %～1 7% ) [5] 。有自身免疫性甲状腺疾病及 …     

阜阳地区妊娠期亚临床甲减诊断标准和筛查策略的探讨

目的:探讨阜阳地区妊娠期亚临床甲减的诊断标准及筛查策略。方法:选取2015年4月至9月于阜阳市人民医院产科门诊建卡注册的孕妇共2421例。患者完成调查问卷,根据既往疾病史分为高危组及低危组,测定甲状腺功能及TPOAb、TGAb。将受试者按下列诊断标准进行诊断:(1)国外标准组:根据2011年ATA指南建立。(2)我国标准组:根据2012年"中国妊娠和产后甲状腺诊治指南推荐标准"建立。比较上述诊断方法所得亚临床甲减患病率的不同,及高危组及低危组的患病率差异。结果:我国标准诊断亚临床甲减的患病率为3.8%,明显低于国外标准18.7%(P0.001);高危组使用我国标准诊断患病率为5.5%,国外标准为24.1%,均高于低危组,但差异无统计学意义(P0.05)。按我国诊断标准,如仅对高危妊娠妇女进行筛查,妊娠合并亚临床甲减的漏诊率为82.7%。结论:应用国外标准诊断阜阳地区妊娠妇女亚临床甲减的患病率明显高于应用我国标准。如仅对妊娠高危人群进行亚临床甲减的筛查,可能会导致高漏诊率。     

汕头地区孕妇甲状腺功能参考值的建立及甲状腺功能异常的筛查

目的建立汕头地区妊娠妇女甲状腺激素功能指标的参考值范围,并依据该参考值了解本地区妊娠妇女甲状腺功能异常的发生情况。 方法对2013年1月至2015年12月期间在汕头大学医学院第二附属医院妇产科门诊就诊的837名妊娠妇女,进行血清甲状腺激素和甲状腺自身抗体检测。其中,2013年1月至2014年6月符合入组标准的367名妊娠妇女的甲状腺功能资料,用于建立本研究妊娠各期血清促甲状腺激素(Thyroid stimulating hormone, TSH)、游离甲状腺素(Free thyroxine, FT₄)的参考值。根据本研究初步建立的参考值,对2014年7月至2015年12月在汕头大学医学院第二附属医院妇产科门诊就诊的470名妊娠妇女进行甲状腺功能异常的筛查。 结果(1)初步建立的汕头地区妊娠妇女孕早、中和晚期血清TSH的正常参考范围分别为：0.07～5.34 mIU/L、0.09～4.96 mIU/L、0.05～6.59 mIU/L,血清FT₄的正常参考范围分别为：8.71～15.53 pmol/L、5.58～11.84 pmol/L、5.57～21.91 pmol/L;(2)本院就诊孕妇甲状腺功能异常的发生率：临床甲亢为1.91%(9/470)、亚临床甲亢为0.64%(3/470)、临床甲减为0、亚临床甲减为1.06%(5/470)。 结论建立汕头地区妊娠妇女甲状腺功能的参考值有利于本地区妊娠妇女甲状腺功能疾病的及时诊断和早期干预,从而减少疾病对孕妇及胎儿造成的影响。     

淄博市不同孕期女性尿碘水平及甲状腺功能状况调查

目的:研究淄博市孕期女性碘营养状况、不同妊娠阶段甲状腺功能变化及妊娠期甲状腺疾病种类分布,制定淄博地区孕期女性特异的血清甲状腺功能指标参考值,为孕期实施碘营养监测及甲状腺功能筛查提供理论依据。方法:选取2013年3月至2014年2月在淄博市妇幼保健院门诊行产检的1268例孕妇。采用化学发光法测定妊娠早、中、晚期孕妇的血清促甲状腺素(TSH)、游离甲状腺素(FT4)、甲状腺过氧化物酶抗体(即TPOAb)。采用酸消化砷一铈接触法测定尿碘水平。结果:1268例孕妇中,孕早、中、晚期尿碘中位数分别为100.3、110.5、105.2,孕早期尿碘水平最低,孕中期尿碘中位数高于孕晚期。孕期FT4参考值范围设定:孕早期12.50~25.10pmmol/L,孕中期12.10~23.10pmmol/L,孕晚期11.20~20.16pmmol/L;孕期TSH参考值范围设定:孕早期0.15~3.20m IU/L,孕中期0.40~3.90m IU/L,孕晚期0.50~4.12m IU/L。正常尿碘组、低尿碘组及高尿碘组的FT4、TSH均在正常范围,高尿碘组、低尿碘组的FT4均低于正常尿碘组(P0.05),3组的TSH值比较差异均无统计学意义(P0.05)。1268例孕妇中,甲状腺功能异常者368例(29.02%),孕早期的甲状腺功能异常发生率高于孕中期及孕晚期,甲状腺功能异常以亚临床型甲减为主,其次为单纯TPOAb阳性。结论:淄博市孕期女性碘营养缺乏严重,需定期监测尿碘水平。随着孕周的增加,FT4值逐渐下降,而TSH值则呈上升趋势;尿碘异常早期可引起FT4的改变,对TSH影响不大。建议在妊娠早期对有甲状腺疾病危险因素的女性积极筛查甲状腺功能。     

泉州地区妊娠中期妇女血清铁与低甲状腺素血症的关系及影响因素

目的:探讨泉州地区妊娠中期妇女血清铁(SI)与低甲状腺素(低T₄)血症间的关系及可能影响因素。方法:回顾分析514例妊娠中期甲状腺过氧化物酶抗体(TPOAb)阴性且非甲亢的妇女,测定SI、体质量指数(BMI)、血脂、游离甲状腺素(FT₄)、促甲状腺激素(TSH)和TPOAb等参数。以SI来标识铁营养状态。采用T检验、卡方检验及多元线性逐步回归等方法进行统计分析。结果:孕妇中位数尿碘浓度130.15μg/L,SI中位数浓度18.88μmol/L,铁缺乏(ID)患病率7.59%(514例)。ID孕妇FT₄水平明显低于非ID孕妇[(13.11±1.76)pmol/L vs (13.97±1.85)pmol/L,P<0.01],低T₄血症患病率明显高于非ID孕妇[39(23.08%) vs 475(12.00%),P<0.05]。在以SI为因变量的多元线性回归模型中,血红蛋白(Hb)、高密度脂蛋白胆固醇(HDL-C)与SI独立正相关(β=0.245,P<0.001;β=0.124,P=0....     

有流产或先兆子痫史的妇女甲状腺自身免疫的研究及其与非器官特异性抗体和甲状腺功能亚临床改变的联系

为研究有流产或先兆子痫史的妇女甲状腺自身抗体的发生率及甲状腺自身抗体与非器官特异性自身抗体的联系,和甲状腺自身抗体的出现与甲状腺功能亚临床改变的关系,分别选取69例患者和健康妇女进行研究。患者分3组:①有≥2次自发性流产(<12周)29例;②至少发生1次不明原因胎儿死亡(>12周)22例;③以前妊娠中曾出现至少2次(间隔6h)血压高于18.7/12.0kPa(140490mmHg),24h蛋白尿高于0.3g/L 18例。通过测定促甲状腺     

Obstetric management of thyroid disease

Timely treatment of thyroid disease during pregnancy is important in preventing adverse maternal and fetal outcome. At present, thyroid testing is performed on symptomatic pregnant women or those with a history of the disease. Hypothyroidism is very often subclinical in nature and not easily recognized without specific screening programs. Even mild maternal thyroid hormone deficiency may lead to neurodevelopment complications in the fetus. Early maternal thyroxine therapy might be beneficial in these women. The main diagnostic indicator of thyroid disease is the measurement of serum thyroid stimulating hormone and free thyroxine. Availability of gestation-age-specific thyroid stimulating hormone (TSH) thresholds is an important aid in the accurate diagnosis and treatment of thyroid dysfunction. Pregnancy-specific free thyroxine thresholds not presently available are also required. Gestational iodine deficiency is still prevalent in some areas of the United Kingdom. Thyroid peroxidase antibody (TPO Ab) in combination with thyroglobulin autoantibody (TgAb) is an accurate predictor of postpartum thyroiditis (PPT). Early screening and treatment of PPT may be justified on the grounds that it is relatively common and causes considerable postpartum morbidity. Large-scale intervention trials are urgently needed to assess the efficacy of preconception or early pregnancy screening for thyroid disorders. Target Audience: Obstetricians & Gynecologists, Family Physicians Learning Objectives: After completion of this article, the reader should be able to state that thyroid gland physiology changes with pregnancy, recall that levels of thyroid hormones are gestational-age related, and explain that accurate interpretation of both antepartum and postpartum levels of thyroid hormones are important in preventing pregnancy-related complication secondary to thyroid dysfunction and in the diagnosis and management of postpartum thyroiditis.     

Thyroid function in pregnant women: iodine deficiency after iodine enrichment program

Abstract

Objective: Significant changes in thyroid function occur during pregnancy which can complicate the interpretation of thyroid function tests. Therefore, normative gestational related reference ranges for thyroid hormones tests are required. The aim of this study was to determine the reference ranges for free triiodothyronine (FT3), free thyroxin (FT4) and thyroid stimulating hormone (TSH) in Iranian pregnant women.

Methods: This study was a cross-sectional observational study conducted in the Obstetrics and Gynecology department, Akbarabadi University Hospital. A single blood sample from 584 pregnant women was analyzed for thyroid function. Serum levels of TSH, FT4, FT3, total T4 (TT4), T3 resin uptake (T3RU) and anti-thyroid peroxidase antibody (TPO Ab) were measured. Urinary iodine was determined in some cases. Reference intervals based on 2.5th and 97.5th percentiles were calculated.

Results: The composition of reference population comprising 584 women included 162 in first trimester and 422 in the third trimester. The 2.5th and 97.5th percentiles values were used to determine the reference ranges for FT3, FT4, TT4, T3RU and TSH. These values were T3 1.4 and 2.9?pmol/L, FT4 7.1 and 18?pmol/L, TT4 7.2 and 13.5?µg/dL and TSH 0.5 and 3.9?µg/L, respectively. The level of urinary iodine in 80.5% of the subjects was less than normal.

Conclusions: Serum levels of thyroid hormones are different in Iranian population that could be due to racial differences or differences in iodine intake.     

Iodine and thyroid hormones during pregnancy and postpartum

Iodine is a trace element essential for synthesis of the thyroid hormones, triiodothyronine and thyroxine. These hormones play a vital role in the early growth and development stages of most organs, especially the brain. The World Health Organization (WHO) has declared that, after famine, iodine deficiency is the most avoidable cause of cerebral lesions including different degrees of mental retardation and cerebral paralysis. The main function of iodine in vertebrates is to interact with the thyroid hormones. During pregnancy sufficient quantities of iodine are required to prevent the appearance of hypothyroidism, trophoblastic and embryonic or fetal disorders, neonatal and maternal hypothyroidism, and permanent sequelae in infants. Thyroid hormone receptors and iodothyronine deiodinases are present in placenta and central nervous tissue of the fetus. A number of environmental factors influence the epidemiology of thyroid disorders, and even relatively small abnormalities and differences in the level of iodine intake in a population have profound effects on the occurrence of thyroid abnormalities. The prevalence of disorders related to iodine deficit during pregnancy and postpartum has increased. Iodine supplementation is an effective measure in the case of pregnant and lactating women. However, it is not implemented and the problem is still present even in societies with theoretically advanced health systems. During pregnancy and postpartum, the WHO recommends iodine intake be increased to at least 200 μg/day. Side-effects provoked by iodine supplementation are rare during pregnancy at the recommended doses.     

Racial comparisons of thyroid function and autoimmunity during pregnancy and the postpartum period

OBJECTIVE: To evaluate thyroid function and the prevalence of thyroid peroxidase (TPO) antibody and autoimmunity in African-American and white women during pregnancy and the postpartum period. METHODS: Five hundred eighty-nine women were evaluated prospectively. Serum thyroid-stimulating hormone (TSH), free thyroxine (T4), and TPO, Ro, and La antibodies were obtained during pregnancy, at delivery, and postpartum. Levels of hCG were determined during pregnancy. Urinary iodine levels were evaluated in the third trimester in another group of women. All TPO antibody-positive patients were to be followed up at 3 and 6 months postpartum. RESULTS: African-American women had lower TSH values than white women at all times. Thyroid-stimulating hormone increased, and free T4 decreased from the first to third trimester of pregnancy for both groups. African Americans had higher hCG levels than whites in the first trimester but not in the third trimester. There was no difference in urine iodine excretion between African-American and white women. Finally, there was no difference in TPO antibody seropositivity between African-American and white women. Overall, 5 patients (0.8%) were diagnosed with subclinical hypothyroidism during pregnancy. CONCLUSION: Fluctuations in TSH and free T4 during pregnancy parallel reported obstetric values. African Americans demonstrated consistently lower TSH levels than whites. These differences were unexplained by racial differences in either TPO antibody seropositivity, iodine status, or chorionic gonadotropin levels.     

Iodine and thyroid hormones during pregnancy and postpartum.

Iodine is a trace element essential for synthesis of the thyroid hormones, triiodothyronine and thyroxine. These hormones play a vital role in the early growth and development stages of most organs, especially the brain. The World Health Organization (WHO) has declared that, after famine, iodine deficiency is the most avoidable cause of cerebral lesions including different degrees of mental retardation and cerebral paralysis. The main function of iodine in vertebrates is to interact with the thyroid hormones. During pregnancy sufficient quantities of iodine are required to prevent the appearance of hypothyroidism, trophoblastic and embryonic or fetal disorders, neonatal and maternal hypothyroidism, and permanent sequelae in infants. Thyroid hormone receptors and iodothyronine deiodinases are present in placenta and central nervous tissue of the fetus. A number of environmental factors influence the epidemiology of thyroid disorders, and even relatively small abnormalities and differences in the level of iodine intake in a population have profound effects on the occurrence of thyroid abnormalities. The prevalence of disorders related to iodine deficit during pregnancy and postpartum has increased. Iodine supplementation is an effective measure in the case of pregnant and lactating women. However, it is not implemented and the problem is still present even in societies with theoretically advanced health systems. During pregnancy and postpartum, the WHO recommends iodine intake be increased to at least 200 microg/day. Side-effects provoked by iodine supplementation are rare during pregnancy at the recommended doses.     

妊娠期亚临床甲状腺功能异常的研究

目的通过检测孕妇妊娠期甲状腺功能,探讨妊娠期亚临床甲状腺功能异常的患病情况及甲状腺过氧化物酶抗体(TPOAb)与甲状腺功能的关系。方法选择2010年10月至2011年7月在北京市海淀妇幼保健院进行常规产前检查的1978例单胎孕妇,并采用系统抽样方法从中抽取TPOAb水平正常(0～9U/ml)的120例妊娠早期(≤12周)和120例妊娠中期(13～24周)孕妇,留取空腹静脉血,检测甲状腺功能及甲状腺自身抗体水平,并对孕妇进行产后随访。结果建立了妊娠早、中期孕妇的促甲状腺激素(TSH)、总甲状腺素(TT4)和游离甲状腺素(FT4)的正常值参考范围。并以此参考值为标准筛出亚临床甲状腺功能减退者82例,单纯低T4血症38例,单纯TPOAb阳性158例,检出率分别为4.15%(82/1978)、1.92%(38/1978)和7.99%(158/1978)。TPOAb阳性组中TSH异常(15.17%)的比例显著高于TPOAb阴性组(6.73%;P<0.001),TPOAb阳性组FT4异常率(7.58%)与TPOAb阴性组(4.98%)比较,差异无统计学意义(P>0.05)。TSH与TPOAb水平呈正相关(r=0.06,P<0.01),但FT4与TPOAb水平无明显相关关系(r=-0.02,P>0.05)。结论 TPOAb阳性与甲状腺功能异常有一定关系,建议妊娠期TPOAb阳性者产后及时复查,监测甲状腺功能的变化。     

Are pregnant women in New Zealand iodine deficient? A cross-sectional survey

Severe iodine deficiency in pregnancy can result in cretinism. There is growing concern that less severe iodine deficiency may also affect fetal growth and development. A handful of prior small New Zealand studies focussed on pregnant women living in Dunedin. This study utilised biochemical, clinical and dietary indices to assess iodine status of 170 women living throughout New Zealand. The median urinary iodine concentration (UIC) of the women was 38 μg/L, well below the 150 μg/L cut-off value that indicates adequate iodine status; 7% of women had goitre. Not surprisingly, iodine intake was also low at 48 μg/day. The majority of women had TSH and FT4 concentrations within pregnant reference ranges, suggesting that despite the low UIC observed in these women, thyroid hormone production appeared unaffected.     

Prevalences of subclinical and overt hypothyroidism with universal screening in early pregnancy

To reveal the prevalence of subclinical and overt hypothyroidism among Turkish population during pregnancy. Also to investigate the prevalence of hypothyroidism using ATA 2017 criteria. This is a cross-sectional study. Patients were consisted of 1416 consecutive pregnant women who were universally screened for thyroid disease in their first trimester between 2013 and 2015. Thyroid-stimulating hormone (TSH) and free T4 (FT4) levels were analyzed during the first antenatal visit (before 12 weeks of gestation). We compared different cutoffs for TSH. We further determined the 2.5th and 97.5th percentiles for TSH and FT4. Initially, the cutoff of 2.5 IU/ml was selected. Accordingly, 305 women (22.3%) had subclinical hypothyroidism and 22 (1.6%) was diagnosed with overt hypothyroidism. When the cutoff was increased to 4 IU/ml, only 40 (2.9%) women were diagnosed with hypothyroidism. Prevalences of overt hypothyroidism and subclinical hypothyroidism were 0.6% and 2.3%, respectively. Universal screening of pregnant women with TSH, using the 2.5 mIU/L cutoff; one in four women was found to be a candidate for thyroid hormone replacement in our cohort. When the cutoff was determined to be 4 mIU/L, prevalence of hypothyroidism decreased approximately 10 times.     

Smoking during pregnancy: a significant cause of neonatal thyroid enlargement

The influence of maternal smoking during pregnancy on the function and the echographic volume of the neonatal thyroid gland was examined in an area of borderline iodine intake (median maternal urinary iodine: 315 range 79-1558 nmol/l). There was a positive correlation (P less than 0.001) between cord serum thiocyanate (SCN) concentrations used as an index of maternal smoking and the maternal smoking habits. The thyroid volume/birthweight ratio increased significantly as a function of SCN values (P less than 0.005): this increase was secondary to a decrease in birthweight as well as to an increase in thyroid volume. There was also a positive correlation between cord serum thyroglobulin (Tg) and SCN levels (P = 0.001). Serum thyroid-stimulating hormone (TSH) and free thyroxine (FT4) values remained within the normal range for age in all newborn infants and were not significantly correlated with SCN values. These results show that smoking during pregnancy in areas with borderline iodine intake may be a significant cause of thyroid enlargement in the newborn.