The Consumption of Food-Based Iodine in the Immediate Pre-Pregnancy Period in Madrid Is Insufficient. San Carlos and Pregnancy Cohort Study

Abstract

A pre-gestational thyroid reserve of iodine is crucial to guarantee the increased demand for thyroid hormone production of early pregnancy. An iodine intake ≥150 µg/day is currently recommended. The objective of this study was to assess average pre-gestational food-based iodine consumption in pregnant women at their first prenatal visit (<12 gestational weeks), and its association with adverse materno-fetal events (history of miscarriages, early fetal losses, Gestational Diabetes, prematurity, caesarean sections, and new-borns large/small for gestational age). Between 2015–2017, 2523 normoglycemic women out of 3026 eligible had data in the modified Diabetes Nutrition and Complication Trial (DNCT) questionnaire permitting assessment of pre-gestational food-based iodine consumption, and were included in this study. Daily food-based iodine intake was 123 ± 48 µg, with 1922 (76.1%) not reaching 150 µg/day. Attaining this amount was associated with consuming 8 weekly servings of vegetables (3.84; 3.16–4.65), 1 of shellfish (8.72; 6.96–10.93) and/or 2 daily dairy products (6.43; 5.27–7.86). Women who reached a pre-gestational intake ≥150 µg had lower rates of hypothyroxinemia (104 (17.3%)/384 (21.4%); p = 0.026), a lower miscarriage rate, and a decrease in the composite of materno-fetal adverse events (0.81; 0.67–0.98). Reaching the recommended iodine pre-pregnancy intake with foods could benefit the progression of pregnancy.

Maternal Iodine Status and Birth Outcomes: A Systematic Literature Review and Meta-Analysis

“…Serum iodide offers an additional measure of iodine status for consideration. In addition, two studies were excluded for using pre-conception measures of iodine status not specified in our pre-defined protocol [ 55 , 56 ]. However, this timeframe is very relevant and may offer a good measure of maternal iodine resources early in pregnancy.…”

The Selection of the Optimal Impregnation Conditions of Vegetable Matrices with Iodine

“…The daily requirement for iodine is 150 mcg/day. Food enrichment offers significant benefits, from reducing the prevalence of nutritional deficiencies to providing benefits for societies and economies [ 6 , 7 , 8 , 9 , 10 , 11 ].…”

Report of the Scientific Committee of the Spanish Agency for Food Safety and Nutrition (AESAN) on the nutritional status of women of childbearing age, during pregnancy and lactation with respect to adequate iodine intake

“…In the Di@bet study, it was observed that the uneducated population used less iodized salt than the group with primary or secondary education (OR (odds ratio): 1.73; 95 %; CI (confidence interval): 1.39-2.16) or university education (OR: 2.23; 95 %; CI: 1.71-2.92) (Soriguer et al, 2012). Also, in the study carried out by Melero et al (2021) in Madrid it was reported that pregnant women with a lower educational level consumed less iodine. Dairy and fish consumption was also lower in the population with a lower socioeconomic status (FEN, 2013).…”

“…However, very few women would be part of this scenario in Spain. Different studies show a low consumption of iodized salt at the beginning of pregnancy: 33 % in Jaén, 36 % in Catalonia and 40.5 % in Madrid (Santiago et al, 2013) (Torres et al, 2017) (Melero et al, 2021). In Catalonia, only 14 % of pregnant women consumed iodized salt and 2 or more servings of dairy per day (Torres et al, 2017).…”

“…However, iodized salt consumption is probably not the predominant factor in pregnancy. Not all studies in pregnant women show adequate median ioduria (Melero et al, 2021). In a survey conducted in Madrid (Melero et al, 2021) it was observed that only 23.9 % of pregnant women had an estimated revista del comité científico nº 37…”