Evaluation of Trimester specific Thyroid Function Hormone Assay in Pregnant Females

Abstract

Introduction: Pregnancy is a physiological phenomenon in which there is the maternal adjustment of multiple organ systems, including metabolic and hormonal adjustments, to supply adequate nutrition to the fetus. Thyroid hormones are necessary to ensure the healthy development of the fetus, especially during the first trimester, during which the fetus is entirely dependent on the maternal thyroid supply delivered through the placenta. during pregnancy, there is increased maternal renal iodine loss, increased levels of serum total thyroxine binding globulin (TBGs), and increaseddegradation of thyroid hormone by placental enzymes. Human chorionic gonadotropin (HCG) has a striking structural resemblance with thyroid-stimulating hormone (TSH), leading to an increase in
thyroid hormone production during pregnancy followed by a plateau phase around 16 weeks of gestation. In pregnancy, overt hypothyroidism is seen in 0.2% cases and sub clinical hypothyroidism in 2.3% cases. Fetal loss, fetal growth restriction, pre-eclampsia and preterm delivery are the usual complications of overt hyperthyroidism (low TSH and high T3, T4) seen in 2 of 1000 pregnancies
whereas mild or sub clinical hyperthyroidism (suppressed TSH alone) is seen in 1.7% of pregnancies and not associated with adverse outcomes.