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Trimester-specific reference intervals of thyroid function tests in Turkish pregnants
Oktay Bulur1, Zeliha Atak2, Derun Taner Ertugrul1
1Department of Internal Medicine, Ankara Kecioren Egitim ve Arastirma Hastanesi, Ankara, Turkey.
Summary
This study establishes trimester-specific thyroid hormone reference ranges for pregnant Turkish women. These population-specific intervals for thyroid-stimulating hormone (TSH), free T3 (fT3), and free T4 (fT4) are crucial for accurate pregnancy care.
Area of Science:
- Endocrinology
- Reproductive Medicine
- Clinical Chemistry
Background:
- Thyroid hormone levels physiologically change during pregnancy.
- Accurate interpretation requires trimester-specific reference intervals.
- International guidelines advocate for population-specific ranges.
Purpose of the Study:
- To determine trimester-specific thyroid function reference intervals for pregnant women in the Turkish population.
- To provide data for accurate thyroid hormone assessment during pregnancy.
Main Methods:
- Chemiluminescence assays (Liaison®) were used for analysis.
- Thyroid function tests (fT3, fT4, TSH) were measured in 1258 pregnant women.
- Participants were categorized into first, second, and third trimesters.
Main Results:
- Established TSH reference intervals: 0.005-3.65 (1st), 0.01-3.63 (2nd), 0.2-3.46 (3rd) mIU/L.
- Established fT4 reference intervals: 0.72-1.79 (1st), 0.71-1.26 (2nd), 0.65-1.12 ng/dL (3rd).
- Established fT3 reference intervals: 2.45-4.03 (1st), 2.37-3.85 (2nd), 2.31-3.77 ng/dL (3rd).
Conclusions:
- Population- and gestational-specific reference intervals are essential for reliable management of thyroid function in pregnant individuals.
- This study provides crucial reference data for the Turkish population.
