Biomaterial Database

Interpretation of in-vitro thyroid function tests during pregnancy. 1983

S C Smith, and A M Bold

In-vitro thyroid function tests are difficult to interpret in pregnancy because of, among other things, the effect of oestrogens on thyroid binding globulin (TBG) concentrations. In an attempt to clarify the position, serum concentrations of total thyroxine (T4), free T4, TBG, T4/TBG ratio, tri-iodothyronine (T3) and thyroid stimulating hormone (TSH) were measured. Total T4 and TBG concentrations rose to above the non-pregnant reference range by 20 weeks. The T4/TBG ratio fell to hypo-thyroid values by 20 weeks but although the free T4 level was lower in the third trimester compared with values in the first and second trimesters, only a few subjects had hypothyroid values. The TSH values remained unchanged throughout pregnancy. The significance of these changes is discussed and reference ranges for these hormones at each trimester are provided.

UI	MeSH Term	Description	Entries
D011247	Pregnancy	The status during which female mammals carry their developing young (EMBRYOS or FETUSES) in utero before birth, beginning from FERTILIZATION to BIRTH.	Gestation,Pregnancies
D012016	Reference Values	The range or frequency distribution of a measurement in a population (of organisms, organs or things) that has not been selected for the presence of disease or abnormality.	Normal Range,Normal Values,Reference Ranges,Normal Ranges,Normal Value,Range, Normal,Range, Reference,Ranges, Normal,Ranges, Reference,Reference Range,Reference Value,Value, Normal,Value, Reference,Values, Normal,Values, Reference
D005260	Female		Females
D006801	Humans	Members of the species Homo sapiens.	Homo sapiens,Man (Taxonomy),Human,Man, Modern,Modern Man
D000293	Adolescent	A person 13 to 18 years of age.	Adolescence,Youth,Adolescents,Adolescents, Female,Adolescents, Male,Teenagers,Teens,Adolescent, Female,Adolescent, Male,Female Adolescent,Female Adolescents,Male Adolescent,Male Adolescents,Teen,Teenager,Youths
D000328	Adult	A person having attained full growth or maturity. Adults are of 19 through 44 years of age. For a person between 19 and 24 years of age, YOUNG ADULT is available.	Adults
D013960	Thyroid Function Tests	Blood tests used to evaluate the functioning of the thyroid gland.	Jostel's TSH Index,Jostel's Thyrotropin Index,Protein-Bound Iodine Test,SPINA-GD,SPINA-GT,Secretory Capacity of the Thyroid Gland,Sum Activity of Peripheral Deiodinases,Thyrotroph Thyroid Hormone Sensitivity Index,Thyroid Gland Function Tests,Function Test, Thyroid,Iodine Test, Protein-Bound,Jostel TSH Index,Jostel Thyrotropin Index,Jostel's TSH Indices,Jostels TSH Index,Jostels Thyrotropin Index,Protein Bound Iodine Test,Protein-Bound Iodine Tests,TSH Index, Jostel's,Test, Protein-Bound Iodine,Test, Thyroid Function,Thyroid Function Test,Thyrotropin Index, Jostel's
D013972	Thyrotropin	A glycoprotein hormone secreted by the adenohypophysis (PITUITARY GLAND, ANTERIOR). Thyrotropin stimulates THYROID GLAND by increasing the iodide transport, synthesis and release of thyroid hormones (THYROXINE and TRIIODOTHYRONINE). Thyrotropin consists of two noncovalently linked subunits, alpha and beta. Within a species, the alpha subunit is common in the pituitary glycoprotein hormones (TSH; LUTEINIZING HORMONE and FSH), but the beta subunit is unique and confers its biological specificity.	Thyroid-Stimulating Hormone,TSH (Thyroid Stimulating Hormone),Thyreotropin,Thyrotrophin,Hormone, Thyroid-Stimulating,Thyroid Stimulating Hormone
D013974	Thyroxine	The major hormone derived from the thyroid gland. Thyroxine is synthesized via the iodination of tyrosines (MONOIODOTYROSINE) and the coupling of iodotyrosines (DIIODOTYROSINE) in the THYROGLOBULIN. Thyroxine is released from thyroglobulin by proteolysis and secreted into the blood. Thyroxine is peripherally deiodinated to form TRIIODOTHYRONINE which exerts a broad spectrum of stimulatory effects on cell metabolism.	L-Thyroxine,Levothyroxine,T4 Thyroid Hormone,3,5,3',5'-Tetraiodothyronine,Berlthyrox,Dexnon,Eferox,Eltroxin,Eltroxine,Euthyrox,Eutirox,L-3,5,3',5'-Tetraiodothyronine,L-Thyrox,L-Thyroxin Henning,L-Thyroxin beta,L-Thyroxine Roche,Levo-T,Levothroid,Levothyroid,Levothyroxin Deladande,Levothyroxin Delalande,Levothyroxine Sodium,Levoxine,Levoxyl,Lévothyrox,Novothyral,Novothyrox,O-(4-Hydroxy-3,5-diiodophenyl) 3,5-diiodo-L-tyrosine,O-(4-Hydroxy-3,5-diiodophenyl)-3,5-diiodotyrosine,Oroxine,Sodium Levothyroxine,Synthroid,Synthrox,Thevier,Thyrax,Thyroxin,Tiroidine,Tiroxina Leo,Unithroid,L Thyrox,L Thyroxin Henning,L Thyroxin beta,L Thyroxine,L Thyroxine Roche,Levo T,Thyroid Hormone, T4
D013975	Thyroxine-Binding Proteins	Blood proteins that bind to THYROID HORMONES such as THYROXINE and transport them throughout the circulatory system.	Thyroxine Transport Protein,Thyroxine-Binding Protein,Thyroxine Binding Protein,Thyroxine Binding Proteins