[Reference values and variability study of thyroid hormones in pregnant women from El Bierzo].

Background And Objectives: El Bierzo area is characterized by low urinary iodine levels in the pregnant population. Guidelines recommend that local reference values are established for the diagnosis of thyroid dysfunction in pregnancy. Our objectives were to establish reference values for thyroid-stimulating hormone (TSH), free thyroxine (FT4) and free triiodothyronine (FT3) in women in the first trimester of pregnancy and to explore the factors influencing variability in these hormones.

[Assessment of iodine nutritional status and thyroxine levels in pregnant women from different geographic areas of the Castile and Leon].

Background And Objectives: Iodine nutritional status in pregnant women is important for neuronal development of the fetus, and may vary depending on the geographic area. Thyroid function and urinary iodine excretion were therefore assessed in pregnant women from three different provinces of a large Spanish autonomous community.

Patients And Methods: A descriptive study was conducted in the three healthcare areas of Burgos, Avila, and Ponferrada on 1,200 women in the first trimester of pregnancy The study consisted of a survey and thyroid hormone and urinary iodine measurements.