Thyroid dysfunction in pregnancy: definition of TSH cut-off should precede the decision of screening in low-risk pregnant women.
OBJECTIVE
To evaluate the frequency of elevated TSH in pregnant women of low risk for thyroid dysfunction.


METHODS
TSH was measured in 838 pregnant women during the first trimester of gestation (from 6 to 14 weeks, median 9 weeks) and who were considered to be of low risk for thyroid dysfunction because they did not meet any of the following criteria: known or clinically suspected thyroid disease; history of head and neck radiotherapy; personal history of autoimmune diseases; family history of thyroid disease; history of abortion or prematurity.


RESULTS
The frequency of elevated TSH was 0.25%, 1.2% and 5.5% at cut-off values of 4, 3 and 2.5?mIU/l, respectively. These rates increase to 1.43%, 2.4% and 6.2% if cases of TSH> 2 mIU/l with TPOAb are included. TSH was undetectable in 18 women (2.1%), but only six (0.71%) had elevated T4.


CONCLUSIONS
The definition of a TSH cut-off that defines subclinical hypothyroidism (SCH) should precede the decision of screening pregnant women without any risk factors for thyroid dysfunction.
Rosario
Pedro W
PW
Postgraduation Program, Santa Casa de Belo Horizonte, Minas Gerais, Brazil. pedrorosario@globo.com
Purisch
Saulo
S
D000293:Adolescent; D000328:Adult; D016009:Chi-Square Distribution; D005260:Female; D006801:Humans; D008403:Mass Screening / Q000379:methods; D011247:Pregnancy; D011248:Pregnancy Complications / Q000097:blood / Q000503:physiopathology*; D011446:Prospective Studies; D012307:Risk Factors; D013959:Thyroid Diseases / Q000097:blood / Q000175:diagnosis / Q000503:physiopathology*; D013972:Thyrotropin / Q000097:blood*; D055815:Young Adult
D013972:Thyrotropin