Skip Navigation
Skip to contents

Endocrinol Metab : Endocrinology and Metabolism


Author index

Page Path
Andrea Gomez  (Gomez A) 1 Article
Thyroid-Stimulating Hormone Reference Ranges in the First Trimester of Pregnancy in an Iodine-Sufficient Country
Carmen Castillo, Nicole Lustig, Paula Margozzini, Andrea Gomez, María Paulina Rojas, Santiago Muzzo, Lorena Mosso
Endocrinol Metab. 2018;33(4):466-472.   Published online November 30, 2018
  • 5,215 View
  • 80 Download
  • 8 Citations
AbstractAbstract PDFPubReader   ePub   

Thyroid dysfunction is associated with negative neonatal and obstetric outcomes. Large differences in thyroid function reference intervals exist across different populations. These differences can be explained by population-specific factors, such as iodine status. Many countries in Latin America report iodine sufficiency, but relatively few countries have published up-to-date data on iodine levels and thyroid function in the overall population, and especially in pregnant women. We evaluated the iodine status of pregnant women in Chile and determined thyroid hormone reference ranges in this population.


This was a prospective observational study of healthy Chilean women at their first prenatal visit before week 14. Thyroid-stimulating hormone (TSH), total thyroxine (T4), free T4, antithyroid peroxidase antibody (TPOAb), and iodine levels from spot urine samples were measured. Iodine status and the reference ranges for TSH were calculated.


A total of 1,022 pregnant women in the first trimester were selected. Urinary iodine levels were measured in 302 randomly-selected women. The median urinary iodine concentration was 173.45 µg/L (interquartile range, 108.11 to 249.35).The reference ranges of TSH were calculated in 670 patients selected according to the National Academy of Clinical Biochemistry guidelines. The median TSH level was 1.88 µIU/mL (2.5th percentile: 0.13 to 97.5th percentile: 5.37). Using the reference range in the 1,022 women, the prevalence of clinical hypothyroidism was 1.76%, and that of subclinical hypothyroidism was 3.92%. TPOAb positivity was more common in women with TSH levels above 3.5 µIU/mL.


We found adequate iodine intake and a right-shifted distribution of serum TSH levels in pregnant women in Chile. The prevalence of hypothyroidism in our sample of pregnant women was higher than has been described in the literature.


Citations to this article as recorded by  
  • Long-term impact of hypothyroidism during gestation and lactation on the mammary gland
    Fiorella Campo Verde Arboccó, Fabio A. Persia, Leila Zyla, Nicolás Bernal, Verónica C. Sasso, Flavia Santiano, Silvina Gomez, Flavia Bruna, Virginia Pistone-Creydt, Constanza Lopez-Fontana, Graciela A. Jahn, María Belén Hapon, Ruben W. Carón
    Journal of Developmental Origins of Health and Disease.2023; 14(1): 122.     CrossRef
  • Evaluation of first and second trimester maternal thyroid profile on the prediction of gestational diabetes mellitus and post load glycemia
    Daniela Mennickent, Bernel Ortega-Contreras, Sebastián Gutiérrez-Vega, Erica Castro, Andrés Rodríguez, Juan Araya, Enrique Guzmán-Gutiérrez, Surangi Nilanka Jayakody Mudiyanselage
    PLOS ONE.2023; 18(1): e0280513.     CrossRef
  • Clinical and histopathological features of follicular thyroid cancer in Chile
    René Díaz, José Miguel Domínguez, Hernán Tala, Roberto Olmos, Pedro Pineda, Daniela Olivarí, Marcela Jiménez, Ximena Mimica, Alejandra Lanas, Gerson Ocares, Jorge Sapunar
    Archives of Endocrinology and Metabolism.2023;[Epub]     CrossRef
  • Effect of the Cut-Off Level for Thyroid-Stimulating Hormone on the Prevalence of Subclinical Hypothyroidism among Infertile Mexican Women
    Lidia Arce-Sánchez, Salvatore Giovanni Vitale, Claudia Montserrat Flores-Robles, Myrna Souraye Godines-Enriquez, Marco Noventa, Carmen Marcela Urquia-Figueroa, Nayeli Martínez-Cruz, Guadalupe Estrada-Gutierrez, Salvador Espino y Sosa, José Romo-Yañez, Ara
    Diagnostics.2021; 11(3): 417.     CrossRef
  • Subclinical hypothyroidism in pregnancy
    Freddy J.K. Toloza, Sanaz Abedzadeh-Anaraki, Spyridoula Maraka
    Current Opinion in Endocrinology, Diabetes & Obesity.2019; 26(5): 225.     CrossRef
  • Letter: Thyroid-Stimulating Hormone Reference Ranges in the First Trimester of Pregnancy in an Iodine-Sufficient Country (Endocrinol Metab 2018;33:466-72, Carmen Castillo et al.)
    Hyemi Kwon
    Endocrinology and Metabolism.2019; 34(1): 93.     CrossRef
  • Response: Thyroid-Stimulating Hormone Reference Ranges in the First Trimester of Pregnancy in an Iodine-Sufficient Country (Endocrinol Metab 2018;33:466–72, Carmen Castillo et al.)
    Lorena Mosso
    Endocrinology and Metabolism.2019; 34(2): 213.     CrossRef
  • Thyroid-Stimulating Hormone Reference Ranges in Early Pregnancy: Possible Influence of Iodine Status
    Tae Yong Kim
    Endocrinology and Metabolism.2018; 33(4): 445.     CrossRef
Close layer

Endocrinol Metab : Endocrinology and Metabolism