Trimester-Specific Reference Intervals for Thyroid Function Parameters in Indian Pregnant Women during Final Phase of Transition to Iodine Sufficiency.

Background: Interpretation of thyroid function tests during pregnancy depends on gestational age, method, and population-specific reference intervals. Therefore, there is a worldwide trend to establish trimester-specific levels for different populations. The aim of this study was to establish a trimester-specific reference range for thyroid function parameters during pregnancy in Indian women.