Thyroid Stimulating Hormone (TSH)
| Units |
Nonpregnant Adult |
First Trimester |
Second Trimester |
Third Trimester |
|
µIU/mL or mIU/L |
0.34 - 4.25 |
0.6 - 3.4 |
0.37 - 3.6 |
0.38 - 4.04 |
|
mU/L |
0.34 - 4.25 |
0.6 - 3.4 |
0.37 - 3.6 |
0.38 - 4.04 |
Some causes of elevated TSH include primary
hypothyroidism (Hashimotos thryroiditis), TSH secreting pituitary tumor, thyroid
hormone resistance, insufficient T4
therapy for hypothyroidism, adrenal insufficiency, iodine, lithium, and antithyroid drugs.
Some causes of low TSH levels include, hyperthyroidism (Graves' disease),
stimulation of the TSH receptor by hCG (first trimester of pregnancy,
hyperemesis gravidarum, molar pregnancy/choriocarcinoma), exogenous thyroid
hormone, thyroiditis, an autonomous thyroid nodule, dopamine, glucocorticoids,
secondary hypothyroidism.
References:
1. Abbassi-Ghanavati M, Greer LG, Cunningham FG. Pregnancy and laboratory
studies: a reference table for clinicians. Obstet Gynecol. 2009
Dec;114(6):1326-31. PMID:19935037
2.
Brent GA.Maternal thyroid function: interpretation of thyroid function tests
in pregnancy.Clin Obstet Gynecol. 1997 Mar;40(1):3-15.
PMID: 9103946 |
|
