Indian Journal of Medical Biochemistry

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VOLUME 21 , ISSUE 1 ( January-June, 2017 ) > List of Articles


Specific Reference Intervals of Serum Triiodothyronine, Thyroxine, and Thyroid-stimulating Hormone in Normal Pregnant Indian Women as per Trimester

Nandita Hazra, Binay Mitra, Reetika Pal

Citation Information : Hazra N, Mitra B, Pal R. Specific Reference Intervals of Serum Triiodothyronine, Thyroxine, and Thyroid-stimulating Hormone in Normal Pregnant Indian Women as per Trimester. Indian J Med Biochem 2017; 21 (1):17-21.

DOI: 10.5005/jp-journals-10054-0012

License: CC BY 3.0

Published Online: 01-12-2012

Copyright Statement:  Copyright © 2017; The Author(s).



Maternal thyroid hormone levels during pregnancy are vital for the health of the mother as well as the developing child. Fetal growth is affected by maternal thyroid levels. Various physiological changes like alterations of thyroxine-binding globulins, human chorionic gonadotropin level, and changes in iodide metabolism affect maternal thyroid hormone levels. Therefore, reference intervals (RIs) for thyroid hormones in pregnant population require to be established separately from the general population.

Materials and methods

The RIs of serum triiodothyronine (T3), thyroxine (T4), and thyroid-stimulating hormone (TSH) were determined in healthy pregnant women by enzyme-linked immunosorbent assay (ELISA) technique after segregating them into three trimesters. This study was conducted in a 492-bedded zonal-level hospital. The reference population was chosen from a study population of pregnant women by strict inclusion and exclusion criteria. The assays were done by the most-commonly used, economical ELISA method employing standard kits. Tests were done using accurate and precise methods with proper quality control measures.


The RIs were calculated from the central 95% of distribution of total T3, total T4, and TSH values located between 2.5 and 97.5 percentile values. The 0.90 confidence intervals for the upper and lower reference limits were calculated. The values thus obtained were different from those provided by the manufacturer kit literature.


It is recommended to determine one's own laboratory-specific, method-specific, trimester-wise RIs for maternal thyroid hormone status and use them for screening of pregnant women.

How to cite this article

Chakrabarty BK, Mitra B, Pal R, Hazra N. Specific Reference Intervals of Serum Triiodothyronine, Thyroxine, and Thyroid-stimulating Hormone in Normal Pregnant Indian Women as per Trimester. Indian J Med Biochem 2017;21(1):17-21.

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