Background: Thyroid disease in pregnancy is a common clinical problem. Since the guidelines for the management of these disorders by the American Thyroid Association (ATA) were first published in 2...

https://www.thyca.org/download/document/486/PregnancyandPostpartum.pdf

2017 Guidelines of the American Thyroid Association for the Diagnosis and Management of Thyroid Disease During Pregnancy and the Postpartum

https://www.thelancet.com/pdfs/journals/lancet/PIIS0140-6736(07)60076-2.pdf

Child development: risk factors for adverse outcomes in developing countries

Summary
The diets of over two-thirds of the world's population lack one or more essential mineral elements. This can be remedied through dietary diversification, mineral supplementation, food fortification, or increasing the concentrations and/or bioavailability of mineral elements in produce (biofortification). This article reviews aspects of soil science, plant physiology and genetics underpinning crop biofortification strategies, as well as agronomic and genetic approaches currently taken to biofortify food crops with the mineral elements most commonly lacking in human diets: iron (Fe), zinc (Zn), copper (Cu), calcium (Ca), magnesium (Mg), iodine (I) and selenium (Se). Two complementary approaches have been successfully adopted to increase the concentrations of bioavailable mineral elements in food crops. First, agronomic approaches optimizing the application of mineral fertilizers and/or improving the solubilization and mobilization of mineral elements in the soil have been implemented. Secondly, crops have been developed with: increased abilities to acquire mineral elements and accumulate them in edible tissues; increased concentrations of ‘promoter’ substances, such as ascorbate, β-carotene and cysteine-rich polypeptides which stimulate the absorption of essential mineral elements by the gut; and reduced concentrations of ‘antinutrients’, such as oxalate, polyphenolics or phytate, which interfere with their absorption. These approaches are addressing mineral malnutrition in humans globally.

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Biofortification of crops with seven mineral elements often lacking in human diets--iron, zinc, copper, calcium, magnesium, selenium and iodine.

Pregnancy has a profound impact on the thyroid gland and thyroid function. The gland increases 10% in size during pregnancy in iodine-replete countries and by 20%– 40% in areas of iodine deficiency. Production of thyroxine (T4) and triiodothyronine (T3) increases by 50%, along with a 50% increase in the daily iodine requirement. These physiological changes may result in hypothyroidism in the later stages of pregnancy in iodine-deficient women who were euthyroid in the first trimester. The range of thyrotropin (TSH), under the impact of placental human chorionic gonadotropin (hCG), is decreased throughout pregnancy with the lower normal TSH level in the first trimester being poorly defined and an upper limit of 2.5 mIU/L. Ten percent to 20% of all pregnant women in the first trimester of pregnancy are thyroid peroxidase (TPO) or thyroglobulin (Tg) antibody positive and euthyroid. Sixteen percent of the women who are euthyroid and positive for TPO or Tg antibody in the first trimester will develop a TSH that exceeds 4.0 mIU/L by the third trimester, and 33%–50% of women who are positive for TPO or Tg antibody in the first trimester will develop postpartum thyroiditis. In essence, pregnancy is a stress test for the thyroid, resulting in hypothyroidism in women with limited thyroidal reserve or iodine deficiency, and postpartum thyroiditis in women with underlying Hashimoto’s disease who were euthyroid prior to conception. Knowledge regarding the interaction between the thyroid and pregnancy/the postpartum period is advancing at a rapid pace. Only recently has a TSH of 2.5 mIU/L been accepted as the upper limit of normal for TSH in the first trimester. This has important implications in regards to interpretation of the literature as well as a critical impact for the clinical diagnosis of hypothyroidism. Although it is well accepted that overt hypothyroidism and overt hyperthyroidism have a deleterious impact on pregnancy, studies are now focusing on the potential impact of subclinical hypothyroidism and subclinical hyperthyroidism on maternal and

/pdf/guidelines-of-the-american-thyroid-association-for-the-1oqnx3mmj9.pdf

Guidelines of the American Thyroid Association for the Diagnosis and Management of Thyroid Disease During Pregnancy and Postpartum The American Thyroid Association Taskforce on Thyroid Disease During Pregnancy and Postpartum

Food and Agricultural Organization of the United Nations PA N I S F I A T G u id e in e s o n fo o d fo r tific atio n w th m ic r o n u tr ie n ts Interest in micronutrient malnutrition has increased greatly over the last few years. One of the main reasons is the realization that micronutrient malnutrition contributes substantially to the global burden of disease. Furthermore, although micronutrient malnutrition is more frequent and severe in the developing world and among disadvantaged populations, it also represents a public health problem in some industrialized countries. Measures to correct micronutrient deficiencies aim at ensuring consumption of a balanced diet that is adequate in every nutrient. Unfortunately, this is far from being achieved everywhere since it requires universal access to adequate food and appropriate dietary habits. Food fortification has the dual advantage of being able to deliver nutrients to large segments of the population without requiring radical changes in food consumption patterns.

Guidelines on food fortification with micronutrients

Background Endemic cretinism, caused by severe iodine deficiency during pregnancy, is the world's most common preventable cause of mental retardation. It can be prevented by iodine treatment before conception, but whether it can be prevented or ameliorated by treatment during pregnancy or after delivery is not known. Methods In a severely iodine-deficient area of the Xinjiang region of China, we systematically administered iodine to groups of children from birth to three years of age (n=689) and women at each trimester of pregnancy (n=295); we then followed the treated children and the babies born to the treated women for two years. We used three independent measures of neural development: the results of the neurologic examination, the head circumference (which correlates with brain weight in the first postnatal year), and indexes of cognitive and motor development. Untreated children one to three years of age, who were studied when first seen, served as control subjects. Results The prevalence of moderat...

https://www.nejm.org/doi/pdf/10.1056/NEJM199412293312603

Timing of Vulnerability of the Brain to Iodine Deficiency in Endemic Cretinism

Iodination of irrigation water as a method of supplying iodine to a severely iodine-deficient population in Xinjiang, China.

Hotien prefecture, Xinjiang Province, China, in the Taklamakan Desert, is an area of severe iodine deficiency. Because usual methods of iodine supplementation failed here, we began supplementation in 1992 with potassium iodate, which was added to irrigation water (Lancet 1994; 334:107-110). We report 4 y experience with this method in 3 townships that contained a total treated population of 37,000. Potassium iodate was dripped into irrigation water (to a concentration 10-80 microg/l) during a 2- to 4-wk period. During the 3 y that followed, no further supplementation was made, and iodine concentrations increased several fold in crops and plants, sheep and chicken thyroid glands, and meat and in urine of children 2-6 y of age and of women who were of childbearing age. Infant mortality decreased 50%, and sheep production increased 43%. Iodine repletion of soil through irrigation water is an effective and cost-efficient way of providing iodine in appropriate situations.

G. R. Delong

Papers

Timing of Vulnerability of the Brain to Iodine Deficiency in Endemic Cretinism

Iodination of irrigation water as a method of supplying iodine to a severely iodine-deficient population in Xinjiang, China.

Dynamics of environmental supplementation of iodine : Four years' experience of iodination of irrigation water in Hotien, Xinjiang, China