Iodine in Pregnancy

Iodine in Pregnancy

The pregnancy

The right amount of iodine during pregnancy (or gestation) is essential for the correct and complete development of the fetus .

In itself, pregnancy is a female physiological state which takes place starting from the embryonic implantation   in the uterine endometrium ; the duration of this condition fluctuates around 38 weeks (with due subjective differences), during which the needs and requirements of the pregnant woman, and of the fruit of conception, are in continuous evolution.Energy, plastic nutrients and essential molecules or microelements must meet the basic and daily needs of the mother, as well as the development and growth of the fetus.

To learn more, read: pregnancy diet »



Specifically, the dietary iodine intake for an adult woman is around 150 micrograms (µg)/day and the increase in the recommended ration in case of pregnancy is equal to 25µg/day; ultimately, the iodine intake during pregnancy should be around 175µg/day .


Iodine-rich foods

Ranking of food sources of iodine:

  • Fish and fishery products 50-100mcgr per 100g of edible portion
  • Human milk 30-70mcgr per 100g of edible portion
  • Fruits , vegetables , cereals and meat 2-5mcgr/100g of edible portion

NB: In order to prevent iodine deficiency which characterizes the entire peninsula, it is recommended to consume table salt (sodium chloride) integrated with iodine for at least 2/3 of the total use. Unfortunately, to date the consumption of iodized salt does not yet reach sufficient levels to prevent iodine deficiency in the diet of Italians.



Iodine is a fundamental constituent of thyroid hormones , therefore its function correlates directly with the specific action of its hormones: T4 (tetraiodothyronine) and T3 (triiodothyronine) . Large sample surveys on dietary iodine consumption and the relative appearance of deficiency symptoms have shown that, on average, the amount of iodine introduced with food DOES NOT reach the minimum requirement for correct organic functioning; however, it must be specified that an iodine intake of 30-40mcgr/day seems sufficient to avoid hormonal alterations of T4 and T3.


Effects of Deficiency

In 1990, the World Health Organization (WHO) estimated that over 20 million people worldwide suffer from brain impairment due to iodine deficiency in the diet; these data place the low-iodine diet in first place in the world ranking of preventable causes with respect to mental deficits.
The specific symptom of iodine deficiency is goiter , i.e. an anatomical alteration characterized by the increase of the pituitary hormone Thyroid Stimulating Hormone (TSH) , in fact, this condition is justified by the hyper-stimulation of the thyroid gland and by its increase in volume. This reaction is aimed at optimizing the uptake, fixation and extraction of the greatest possible amount of circulating blood iodine.


Iodine excess

Very rare but still noteworthy is the super dosage; in this case toxic goiter (Plummer’s disease) and hyperthyroidism may appear .


Importance in Pregnancy

Iodine in pregnancy is essential in order to prevent complications in fetal development ; however, according to the Recommended Nutrient Intake Levels for the Italian population (LARN), the assessment and dietary correction of iodine intake must necessarily be carried out in the pre-pregnancy period. Otherwise, similarly to the lack of the gestational period, the pre-pregnancy deficit can favor:

  • abortion
  • increase in peri-natal mortality
  • congenital anomalies
  • neurological alterations
  • mental deficit.

It seems that these complications, linked to iodine deficiency during pregnancy (especially in the first two trimesters) and its scarce intake in the pre-pregnancy period, can be easily prevented by guaranteeing only 1 mcg/kg of body weight/ day ; however, estimating the average gestational weight reached in Italy, a similar intake would hardly cover even 40-50% of the recommended daily ration.
Ultimately, in order to prevent complications on the fetus induced by hypo-iodine malnutrition in the pregnant woman, it is advisable to verify that the pre-pregnancy iodine intake reaches 150mcgr/day and that the iodine intake during pregnancy (especially in first two trimesters) is equal to 175 mcgr/day.



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