[Iodine intake during pregnancy: effects on thyroid function in mother and child]. / Ingesta de yodo durante el embarazo: efectos en la función tiroidea materna y neonatal.

INTRODUCTION: Recent studies in Spain have shown an inadequate iodine intake in a significant proportion of pregnant women. Pregnancy increases thyroid hormone requirements, and adequate iodine intake is therefore needed. MATERIAL AND METHODS: One hundred and forty-seven women in their third trimester (week 37) of pregnancy provided a blood sample and a 24-hour urine sample to test serum and urine iodine levels and completed a food frequency questionnaire to assess iodine intake during pregnancy. Serum TSH levels were measured in the babies born to the 140 mothers in the postpartum group. RESULTS: Only 10.9% of pregnant women consumed more than 250 µg iodine daily, and 24.4% of them consumed less than 100 µg daily. Mean free T4 levels were 9.37 pmol/L, and 74 women (54.41%) had levels below the hypothyroxinemia threshold. TSH levels were normal in 135 newborns (96.4%), while 5 (3.6%) had levels higher than 5 µU/mL.

Un enfoque para un problema sanitario y social: yodurias en embarazadas de una región yododeficiente / An approach to a sanitary and social problem: urinary iodine excretion in pregnant women from a iodine deficient region

La yoduria o eliminación urinaria de yodo (EUI) es un método efectivo para detectar el déficit en su ingesta. En 121 embarazadas se midió yoduria en dos muestras (matutina y vespertina) con el método turbidimétrico modificado por Pino. Se consideró normal una EUI =150 ug/l. En las mujeres con EUI<100ug/l se investigó la función tiroidea. De 121 embarazadas la yoduria fue normal en 75, en las que la yoduria matinal no fue diferente a la vespertina (matutina: 305.2 ± 7.0 vs vespertina: 319.2 ± 8.8; NS). No hubo diferencia entre las yodurias de los diversos trimestres. En 46 embarazadas (36.9 por ciento) la yoduria fue baja sin diferencias entre la matutina y vespertina (matutina: 88.12 ± 5.07 µg/l vs 88.7 ± 6.2 µg/l; NS), al igual que entre las yodurias matutinas y vespertinas en los tres trimestres de embarazo. De las embarazadas con yodurias <100ug/l, el 45 por ciento presentó alteraciones de la función tiroidea. No hubo diferencias significativas respecto a la edad entre las embarazadas con baja y normal EUI. La determinación de yoduria matutina y vespertina permitió detectar un mayor número de embarazadas con baja ingesta de yodo y orientó para la búsqueda de disfunción tiroidea que no se hubiera detectado por no contar nuestra Provincia con un Programa de screening para hipotiroidismo gestacional.

The urinary iodine excretion (UIE) assay is an effective method to detect reduced iodine intake. UIE was measured in two different samples (morning and evening) from 121 pregnant women, with a turbid-metric method modified by Pino (normal value =150 ug/l). Furthermore, thyroid function was evaluated in pregnant women with UIE <100 ug/l. From 121 pregnant women, the UIE was normal in 75 with similar morning and evening samples (morning: 305.2 ± 7.0; evening: 319.2 ± 8.8; p: NS). The UIE did no showed differences in different trimesters and in morning and evening samples. The UIE was low in 46 women (36.9 percent), without significant differences between morning and evening (morning: 88.12 ± 5.07 µg/l; evening: 88.7 ± 6.2 µg/l; p: NS). Normal or low UIE were not influenced by the age of pregnant women and 45 percent of pregnant women with UIE <100ug/l showed impaired thyroid function. Morning and evening study of UIE allowed us to detect a higher number of pregnant women with low iodine intake. This study let us to find thyroid function abnormalities likes a screening method, because in our state there is not a public screening program for gestational hypothyroidism.