Salek Tomas, Dhaifalah Ishraq, Langova Dagmar, Havalova Jana
Department of Clinical Biochemistry and Pharmacology, Tomas Bata Hospital in Zlin a. s., Havlickovo nabrezi 600, 76275 Zlin, Czech Republic.
Department of Biomedical Sciences, Faculty of Medicine, University of Ostrava, Syllabova 19, 703 00 Ostrava - Zabreh, Czech Republic.
Biomed Pap Med Fac Univ Palacky Olomouc Czech Repub. 2019 Sep;163(3):265-268. doi: 10.5507/bp.2018.063. Epub 2018 Nov 6.
The aim of this study was to determine the prevalence of maternal hypothyroidism in the first trimester from 11 to 14 weeks of gestation according to the American Thyroid Association (ATA) guidelines from 2017 and to compare the rates for singleton and twin pregnancies.
A total of 4965 consecutive Caucasian singleton pregnancies and 109 Caucasian twin pregnancies were included in the investigation. Patients with a history of thyroid gland disorder were excluded. Subclinical maternal hypothyroidism was defined as a thyroid stimulating hormone (TSH) concentration above the 97.5 percentile and free thyroxine (fT4) within the range of a reference population of women at 11-14 weeks of gestation. Overt maternal hypothyroidism was defined as a TSH concentration above the 97.5 percentile and an fT4 below the 2.5 percentile of the reference population.TSH, fT4, and anti thyroid peroxidase antibody (TPOAb) were measured by immunochemiluminescent assays on an 16200 Abbott Architect analyzer.
The prevalence of hypothyroidism for twin pregnancies was no higher than that for singleton pregnancies; 6.42% (7/109) vs. 5.32% (264/4965), respectively; P=0.61. All twin pregnancies were subclinical. Singleton hypothyroid pregnancies included 4.91% (244 cases) of subclinical and 0.41% (20 cases) of overt hypothyroidism. The prevalence of TPOAb positive hypothyroid women for twin pregnancies and singleton pregnancies was 71% (5/7) vs. 52% (137/264 cases), respectively but the differences were not statistically significant; P=0.31.
Each first trimester screening center should establish its TSH and fT4 reference ranges. Our center had higher upper reference limits of TSH than that of the universally fixed limit of 2.5 mU/L, which led to a lower measured prevalence of maternal hypothyroidism. A large number of hypothyroid women were TPOAb positive.
本研究旨在根据2017年美国甲状腺协会（ATA）指南确定妊娠11至14周孕早期母体甲状腺功能减退症的患病率，并比较单胎和双胎妊娠的患病率。
本研究共纳入4965例连续的白种人单胎妊娠和109例白种人双胎妊娠。排除有甲状腺疾病史的患者。亚临床母体甲状腺功能减退症定义为促甲状腺激素（TSH）浓度高于第97.5百分位数，且游离甲状腺素（fT4）在妊娠11至14周女性参考人群范围内。显性母体甲状腺功能减退症定义为TSH浓度高于第97.5百分位数，且fT4低于参考人群的第2.5百分位数。TSH、fT4和抗甲状腺过氧化物酶抗体（TPOAb）采用免疫化学发光法在雅培Architect 16200分析仪上进行检测。
双胎妊娠甲状腺功能减退症的患病率不高于单胎妊娠；分别为6.42%（7/109）和5.32%（264/4965）；P = 0.61。所有双胎妊娠均为亚临床型。单胎甲状腺功能减退妊娠包括4.91%（244例）亚临床型和0.41%（20例）显性甲状腺功能减退症。双胎妊娠和单胎妊娠中TPOAb阳性甲状腺功能减退女性的患病率分别为71%（5/7）和52%（137/264例），但差异无统计学意义；P = 0.31。
每个孕早期筛查中心都应建立自己的TSH和fT4参考范围。我们中心的TSH参考上限高于普遍固定的2.5 mU/L，这导致母体甲状腺功能减退症的测量患病率较低。大量甲状腺功能减退女性TPOAb呈阳性。
