Upper Limit for TSH of First and Second Trimester Pregnancy in Turkey
Upper Limit for TSH of First and Second Trimester Pregnancy in Turkey
Physiological changes necessitate the use of pregnancy-specific reference ranges for TSH and
 FT4 to diagnose thyroid dysfunction during pregnancy. Although many centers use fixed upper
 limits for TSH of 2.5 or 3.0 mU/L, this may lead to overdiagnosis or even overtreatment.

 The new guidelines of the American Thyroid Association have considerably changed
 recommendations regarding thyroid function reference ranges in pregnancy accordingly. Any
 hospital or physician that is still using the 2.5 or 3.0 mU/l cut-off for TSH during
 pregnancy should evaluate their own lab-specific cut-offs.

 The investigator's objective is to establish a rational reference range of serum TSH for
 diagnosis of subclinical hypothyroidism in the first and second trimester of pregnant women
 in west Black Sea region in Turkey.
Serum thyroid function tests (including T3, T4, TSH, Anti-TPO) will be obtained from the
 singleton pregnancies in first and second trimester to determine the local specific normal
 ranges.
Inclusion Criteria:

 -  Singleton pregnancy

 -  Free of pre-existing thyroid disease

 -  That do not use thyroid interfering medication

 -  That did not undergo IVF treatment

 -  TPOAb negative

 Exclusion Criteria:

 -  Adolescent pregnancy