Iodoprophylaxis in pregnancy and breastfeeding

Iodine is an element that plays an important biological role in humans. The amount of iodine present in our body amounts to about 15-20 mg and is mostly concentrated in the thyroid gland.

Iodine is essential for making thyroid hormones (thyroxine and triiodothyronine). Iodine is taken with the diet, let’s dispel the myth according to which the air and sea water are good for you because they are rich in iodine.

Foods that contain iodine

All food products that originate from the earth’s crust are poor in this element, on the contrary products of marine origin contain it in greater quantities (fish 800-3000 ug/kg; minus sea salt 20-30 ug/kg).

Milk also contains a considerable amount (280 ug/L).

Fruits and vegetables contain minimal amounts. In people whose iodine intake through the diet is low – particularly in inland regions, where the consumption of fish or other foods of marine origin is rare – there is a greater occurrence of goiter.

Basically the thyroid struggles to produce hormones due to the lack of its main element so it increases in volume (goitre) in an attempt to work harder. If iodine continues to be scarce, hypothyroidism occurs.

The iodide assay (urine iodine in a single sample) is used to monitor iodine values ​​in the population.

Methods of iodoprophylaxis: iodized salt

Considering that the consumption of salt is ubiquitous, adding iodine to salt is a simple and economical system that does not alter the organoleptic characteristics of foods. Be careful not to confuse sea salt (it contains iodine but very little 20 ug/kg) with iodized salt (iodine 20 ug/g)!

In Europe, however, less than 50% of families use iodized salt. In Italy a 2005 law makes the availability of iodized salt in shops mandatory, however the coverage with iodized salt is <60%. Fortunately, Italy is a country with a mild degree of iodine deficiency. I remind you that a large part of the iodine requirement, especially in children, is not covered by the intake of iodized salt but by milk.


During pregnancy the maternal thyroid must produce more thyroid hormone (considering that for the first 12 weeks the fetal thyroid is not yet functional), in addition the mother must provide iodine for herself and for the baby .

In the first weeks of fetal life, maternal iodine which crosses the placenta guides the development of the central nervous system of the fetus, therefore it is important that the woman arrives at the beginning of pregnancy with a good reserve of iodine (about 150 ug/day per three months before conception).

Adverse effects of severe iodine deficiency in pregnancy

Maternal and fetal goiter, hypothyroidism, increased risk of miscarriage, perinatal deaths, cretinism in the infant.

Advantages of iodoprophylaxis in pregnancy

Reduction of miscarriage, increase in birth weight, increase in the child’s IQ.

Iodine requirement

Here is an outline of iodine requirements at various stages of life:

Iodine intake :

Adult 150 ug/day

Pregnancy 250 ug/day

Breastfeeding 250 ug/day

Infants 90 ug/day

Children (1-5 years) 90 ug/day

Children (6-12 years) 120 ug/day

To reach 150 ug of iodine per day it is sufficient to drink a cup of milk every day, use fine iodized salt to season foods and eat marine fish 3 times a week (for novice cooks: canned tuna is rich in iodine).

During pregnancy and breastfeeding, on the other hand, it is very difficult to reach 250 ug of iodine per day with food alone, so it is advisable to take a supplement containing iodine. Common multivitamins sold for pregnancy contain about 150ug of iodine.

All these indications are valid for women who do not have a specific thyroid pathology. In fact , the endocrinologist always advises against the intake of iodine for women suffering from hyperthyroidism (hyperfunction of the thyroid gland), which tends to worsen the clinical picture.

Women on the other hand being treated for hypothyroidism (hypofunction of the thyroid gland) need less iodine as they take the ready-made thyroid hormone.

In conclusion In pregnancy and while breastfeeding, an iodine supplement is strongly recommended, as is integration with iron and folate.

Kathryn Barlow is an OB/GYN doctor, which is the medical specialty that deals with the care of women's reproductive health, including pregnancy and childbirth.

Obstetricians provide care to women during pregnancy, labor, and delivery, while gynecologists focus on the health of the female reproductive system, including the ovaries, uterus, vagina, and breasts. OB/GYN doctors are trained to provide medical and surgical care for a wide range of conditions related to women's reproductive health.

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