Iodine in pregnancy

Iodine plays an important role in the human body. It is necessary for the production of thyroid hormones, which in turn regulate all processes occurring in our body: metabolism, vitamin synthesis, the functions of other hormones, tissue regeneration, and blood pressure. A person weighing 70 kg contains 0.12-0.2 mg of the microelement. Its deficiency leads to thyroid disease, poor health, expressed in fatigue, nervousness, headaches, depression, and memory loss. Iodine is especially important during pregnancy for the formation of the fetus. [ 1 ]

Beginning in early pregnancy, maternal thyroid hormone production normally increases by approximately 50% in response to rising serum thyroxine-binding globulin levels (as a result of rising estrogen levels) and to stimulation of thyrotropin (TSH) receptors by human chorionic gonadotropin.[ 2 ] The placenta is a rich source of deiodinase, which enhances the breakdown of thyroxine (T4) to the bioactive reverse triiodothyronine (T3).[ 3 ] Thus, the demand for thyroid hormones increases, requiring an adequate supply of iodine, which is obtained mainly from the diet and/or from supplemental iodine. Additionally, during the second half of pregnancy, fetal thyroid hormone production increases, further contributing to the increased maternal blood iodine requirement, as iodine readily crosses the placenta.

The main route of iodine excretion is through the kidneys, which account for more than 90% of ingested iodine. [ 4 ] In early pregnancy, the glomerular filtration rate of iodide increases by 30-50%, which further reduces the circulating pool of iodine in the plasma. [ 5 ]

Iodine norm during pregnancy

A pregnant woman needs an increased iodine intake, because the fetus takes this element from the mother's body until birth. And the woman herself, due to the increase in hormonal activity, needs a larger volume. According to statistics, 80% of expectant mothers experience iodine deficiency. Therefore, the answer to the question of whether iodine is needed during pregnancy is a clear "yes".

To satisfy the daily needs of yourself and your growing body, you need to receive 0.2 mg of the substance from outside.

The 4th edition of the NNR recommended an additional 25 μg/day during pregnancy (RDI set at 175 μg/day) and an additional 50 μg/day during lactation (RDI set at 200 μg/day) to ensure adequate iodine intake during breastfeeding. These reference values were lower than the reference values of 200 μg/day during pregnancy and 250 μg/day during lactation presented by FAO/WHO in 2005. In addition, WHO/UNICEF/ICCIDD recently increased the reference values for pregnant women from 200 to 250 μg/day.[ 6 ]

Iodine is scattered in nature, but the substance is mostly found in sea water, its inhabitants, and algae. Not everyone is lucky enough to live near the sea, so the problem needs to be solved by other methods.

First of all, eat right, consuming iodine-containing foods: seafood, seaweed, cod liver, beets, black currants, figs, spinach, dairy products, iodized salt, and if necessary, take iodine supplements, but only as prescribed by a doctor. [ 7 ] The results of studies conducted by the US Food and Drug Administration (FDA) have shown that iodine in the United States is mainly found in cereals, milk and cheese. [ 8 ]

The effect of iodine on pregnancy

Under the influence of iodine, the hormones thyroxine (T4) and triiodothyronine (T3) are synthesized, playing a huge role in the functioning of the endocrine and reproductive systems. Iodine deficiency can lead to the following consequences:

• threats of termination of pregnancy;
• mental retardation of the child;
• congenital pathology of the baby's thyroid gland;
• metabolic disorders, excess weight.

If the diet of pregnant women does not contain enough iodine, the fetus cannot produce enough thyroxine and its growth is slowed. The fetus often dies in the womb, many babies die within a week of birth. Current data on brain embryology suggest that the critical time for the effects of iodine deficiency is the middle of the second trimester, i.e. 14-18 weeks of pregnancy. At this time, the neurons of the cerebral cortex and basal ganglia are formed. This is also the time of formation of the cochlea (10-18 weeks), which also greatly affects the development of endemic cretinism. Deficiency of iodine or thyroid hormones that occurs during this critical period of life leads to a slowdown in the metabolic activity of all cells of the fetus and irreversible changes in brain development.

Insufficient iodine levels during pregnancy and the postpartum period result in neurological and psychological deficits in children. [ 9 ], [ 10 ] The prevalence of attention deficit hyperactivity disorder is higher in children living in iodine-deficient areas than in iodine-rich areas. [ 11 ] The intelligence quotient (IQ) of children living in iodine-deficient areas is, on average, 12.45 points lower than those living in areas with normal iodine intake. [ 12 ]

Having made sure whether iodine is possible during pregnancy and its importance in its early stages, the question arises whether the growing organism needs it in the third trimester? All metabolic processes of the future child occur with the participation of the substance, therefore, even if all the main organs are formed, iodine is necessary to strengthen them. [ 13 ], [ 14 ]

Iodine and folic acid during pregnancy

In order to give birth to a physically and mentally healthy child, in addition to iodine, vitamins, especially folic acid, play an equally important role in a woman’s diet. The latter is involved in cell division, the formation of a full-fledged cardiovascular and nervous system, and reduces the risk of miscarriage and congenital defects in the child. In addition, it promotes the absorption of iodine. [ 15 ]

When planning a pregnancy, even before conception, you need to take care to fill your diet with foods rich in B9: legumes, nuts, green salad, citrus fruits, and also take additional folic acid to cover the need for 400 mcg per day when they are trying to get pregnant, and during the first 12 weeks of pregnancy, when the baby's spine is developing. [ 16 ]

If you weren't taking folic acid supplements before you became pregnant, you should start taking them as soon as you find out you're pregnant. You can get them at pharmacies, large supermarkets, health food stores, or with a doctor's prescription.

Similar actions are taken with regard to iodine when planning a pregnancy, but its thoughtless use is not always justified, since not all regions have a deficiency of the substance in the environment; for example, in marine or ocean coastal zones it is in abundance.

In any case, taking the microelement should be preceded by a visit to an endocrinologist, since there may be deviations in the functioning of the thyroid gland that are not associated with pregnancy.

Does it make sense for men to take iodine when planning a pregnancy? Most likely not, since the level of thyroid hormones in the mother determines the stimulation of the corpus luteum functions, which are necessary to maintain pregnancy in the early stages, and their placental transfer to the fetus at the embryonic stage.

Methods of saturating the body with iodine

In addition to the iodine-rich foods mentioned above, special salt enriched with the microelement (used for cooking dishes that are not subjected to heat treatment, otherwise the iodine will simply evaporate) can be used for various medical procedures, provided that there is no excess of it in the body:

• gargle with iodine during pregnancy - many medications are contraindicated for the treatment of tonsillitis, pharyngitis, laryngitis, and oral diseases. In this case, iodine solution can act as an antiseptic and destroy pathogenic microbes. You can prepare it by boiling a glass of water, letting it cool to a warm state and dropping 2-3 drops of iodine into it. Some of it is absorbed by the oral mucosa and enters the bloodstream;
• soda and iodine - adding soda to the solution will give it disinfectant properties, soften the more aggressive action of iodine. The inflamed mucous membrane will respond favorably to the alkaline solution, making it easier to swallow;
• soda, salt and iodine - a classic gargle recipe that will cleanse the mucous membrane, soften it, and have an antibacterial effect. For a glass of water, you will need a spoonful of salt, the same amount of soda and 2 drops of the microelement. Do not exceed the recommended doses. It is best to rinse after meals, not increasing their frequency more than 3-4 times a day, so as not to dry out the mucous membrane;
• Lugol's solution during pregnancy - it is used to lubricate inflamed tonsils and the walls of the larynx. It combines water, potassium iodide and iodine in a ratio of 17:2:1. It may also contain glycerin for a softening effect;
• external use of iodine - during pregnancy, you can lubricate wounds with it, make an iodine mesh in places of bruises and injections;
• water with iodine - to overcome iodine deficiency, even iodized mineral water is produced. Its enrichment with the chemical element is carried out in accordance with the standards necessary for health. This is the simplest and most accessible method of delivering the substance to the body;
• Inhalations with iodine during pregnancy - a few drops of iodine in an inhalation solution will not only help treat colds of the upper respiratory tract, but will also help eliminate iodine deficiency in the body.

Iodine preparations during pregnancy

Many studies have established the benefits of iodine supplementation during pregnancy in areas with severe iodine deficiency.[ 17 ]

An endocrinologist, having conducted a study of the woman’s hormonal background, an ultrasound of the thyroid gland, in order to avoid negative consequences of iodine deficiency for both the pregnant woman and the child, can prescribe special medications and advise on how to take iodine during pregnancy:

• iodine active is a dietary food supplement, the uniqueness of which is its ability to be absorbed when there is a deficiency of the substance and simply excreted from the body when there is an excess. During pregnancy, the recommended dose is 200 mcg once a day during meals;
• potassium iodine - a regulator of thyroxine synthesis, prevents the development of goiter associated with iodine deficiency, normalizes the size of the thyroid gland, affects the required ratio of hormones T3 and T4. Its daily norm during pregnancy is 150-200 mcg. The duration of treatment is determined by the attending physician;
• povidone-iodine suppositories - the drug has an antipathogenic effect. It is prescribed to eliminate vaginal infections. And although the instructions indicate pregnancy as one of the contraindications, it is used not only when planning it, but also after conception.

Bacterial vaginosis, which women in position are often susceptible to due to decreased immunity, can complicate pregnancy and sometimes even terminate it. The doctor, weighing the risks of the disease and the dangers of treatment, often chooses the latter.

In the first trimester, povidone-iodine treatment is the safest, in the second it is not used, a month before delivery it becomes possible again, and with no time limit. If a short course of therapy is enough, then there is nothing to be afraid of at all.

According to NHANES, only 20.3% of pregnant women and 14.5% of breastfeeding women in the United States take iodine supplements.[ 18 ] Currently, 114 of 223 (51%) brands of prenatal and over-the-counter prenatal multivitamins sold in the United States include iodine as an ingredient, and many of those that do contain iodine do not contain the labeled amount.[ 19 ] The Women, Infants, and Children's Nutrition Program has recommended that all prenatal multivitamins given to women in the program contain 150 mcg of iodine per daily serving since 2010.

Substances that interfere with the absorption of iodine

Competitive inhibitors of NIS, such as perchlorate, thiocyanate, and nitrate, can reduce iodine availability to the thyroid gland, thereby potentially worsening the effects of dietary iodine deficiency. Perchlorate comes from a variety of sources, is extremely stable as an inorganic salt, and persists in soil and groundwater for long periods.[ 20 ] In the United States, perchlorate has been detected in many substances, including tobacco, alfalfa, tomatoes, cow's milk,[ 21 ] cucumbers, lettuce, soybeans, eggs, and multivitamins (including prenatal multivitamins). Thiocyanate, a metabolite of cyanide that is formed as a byproduct of cigarette smoke, and nitrate, which is naturally occurring and present in many processed foods, can reduce NIS activity, thereby reducing iodine availability.

Urinary selenium and iodine levels are closely related in pregnant women. [ 22 ] Selenium is an important component of glutathione peroxidase and selonoproteins, which include 3 thyroid hormone deiodinases. Thus, selenium deficiency may lead to accumulation of harmful peroxides in the thyroid gland and impair the peripheral deiodination process required to produce the active thyroid hormone, T3, from T4. A recent study by Negro and colleagues [ 23 ] reported that selenium supplementation at 200 μg/day during pregnancy and the postpartum period reduced the prevalence of permanent maternal hypothyroidism (11.7%) compared with women who did not receive supplements (20.3%) (p < 0.01).

Harm of iodine during pregnancy

Despite the positive aspects of iodine's influence on women's health and the formation of a full-fledged person inside her, its excess is no less harmful than its deficiency. This chemical element is a toxic substance that can lead to:

• poisoning of the body;
• development of thyrotoxicosis;
• dyspeptic disorders;
• muscle weakness;
• hair breakage;
• toxicoderma;
• tachycardia;
• the formation of diffuse goiter;
• weight loss;
• threat of miscarriage;
• intrauterine developmental disorders of the fetus.

Iodine loading in the mother can potentially cause hypothyroidism in the fetus, but not in the mother.[ 24 ]

A new study warns that excessive iodine exposure may also damage maternal thyroid health, and recommends a lower iodine intake limit during pregnancy than the current WHO recommendation of 250 µg per day for pregnant women. [ 25 ] Current recommended tolerable upper limits (TULs) for iodine intake during pregnancy vary widely around the world. The TUL set by the US Institute of Medicine is 1,100 µg per day, [ 26 ] which is higher than the 500 µg per day set by WHO and the European Food Safety Authority.

Excessive iodine intake can cause changes in thyroid function in susceptible individuals [ 27 ]. In normal individuals, excess iodine can cause temporary inhibition of thyroid hormone synthesis by a mechanism known as the acute Wolff-Chaikoff effect. [ 28 ] Increasing dietary iodine intake has been found to be associated with an increased prevalence of thyroid autoantibodies. [ 29 ]

An iodine overdose during pregnancy may be expressed in its taste in the mouth. This may happen with prolonged use of the microelement, in the case of multiple excess of the recommended doses, and simply with iodine intolerance during pregnancy.

Other signs of iodine intoxication include inflammation of the mucous membranes (conjunctivitis, rhinitis, bronchitis), digestive disorders, skin rashes, hoarseness, burning in the throat, and rapid breathing.

These symptoms are an urgent signal to see a doctor.

Iodine for termination of pregnancy

As we can see, iodine is not only good, but can also be bad. It is even used to terminate pregnancy in the early stages without medical intervention. Is this true? In folk medicine, recipes for milk with iodine and sugar with iodine are spread, supposedly helping to get rid of unwanted pregnancy.

Since young people now begin their sexual life early, not yet fully knowing the intricacies of contraception, force majeure situations often arise when it is necessary to terminate a pregnancy before the parents find out about it. Various advice from the Internet comes into play.

In fact, there is no scientific evidence to support this theory. Doctors warn that drinking such a "pregnancy remedy" can cause great harm to your body:

• cause bleeding;
• get serious intoxication, even to the point of disability, and sometimes even death;
• having abandoned the pregnancy after an unsuccessful attempt, to give birth to a disabled child.

If the microelement in the recipe for milk with iodine has a lower concentration, then dripping iodine onto sugar and taking it is generally dangerous.

Termination of pregnancy in the early stages can be done by vacuum or medication, without exposing yourself to great risk.