In humans, iodine plays an important role. It is necessary for the production of thyroid hormones, and they, in turn, are the regulator of all the processes occurring in our body: metabolism, synthesis of vitamins, exercise the functions of other hormones, tissue regeneration, blood pressure. In a person weighing 70 kg contains 0.12-0.2 mg of the trace element. Its deficiency leads to diseases of the thyroid gland, poor health, expressed in fatigue, nervousness, headaches, depression, weakening of memory. Especially important during pregnancy iodine for the formation of the fetus. 
Starting from early pregnancy, the production of maternal thyroid hormone usually increases by about 50% in response to an increase in serum thyroxin-binding globulin (as a result of an increase in estrogen level) and due to stimulation of thyrotropin receptor (TSH) human chorionic gonadotropin.  The placenta is a rich source of deiodinase that enhances the breakdown of thyroxin (T4) to bioactive reverse triiodothyronine (T3).  Thus, the need for thyroid hormones increases, which requires a sufficient supply of iodine, which mainly comes from food and / or in the form of additional iodine. In addition, in the second half of pregnancy, fetal thyroid hormone production increases in the fetus, which further increases the need for iodine in maternal blood, since iodine easily penetrates the placenta.
The main route of iodine elimination is through the kidneys, which account for more than 90% of iodine taken.  In the early stages of pregnancy, the glomerular filtration rate of iodide increases by 30-50%, which further reduces the circulating pool of iodine in the plasma. 
Iodine rate during pregnancy
A pregnant woman needs an increased iodine rate, because the fetus until birth takes this element from the mother's body. And the woman herself due to the increase in hormonal activity needs more volume. According to statistics, 80% of expectant mothers experience iodine deficiency. Therefore, when asked whether iodine is necessary during pregnancy, the unequivocal answer is yes.
In order to satisfy the daily need of oneself and a growing organism, it is necessary to obtain from the outside 0.2 mg of substance.
An additional 25 µg / day during pregnancy (RDI is set to 175 µg / day) and an additional 50 µg / day during lactation (RDI is set to 200 µg / day) were recommended in the 4th edition of the NNR to ensure a sufficient amount of iodine during feeding. These control values were lower than the control values of 200 µg / day during pregnancy and 250 µg / day during lactation, presented by FAO / WHO in 2005. In addition, WHO / UNICEF / ICCID recently increased control values for pregnant women from 200 to 250 µg / day. 
Iodine is dispersed in nature, but most of the substance in sea water, its inhabitants, algae. Not everyone was lucky to live near the sea, so the problem must be solved by other methods.
First of all, eat right by eating iodine-containing products: seafood, sea kale, cod liver, beets, black currants, figs, spinach, dairy products, iodized salt, and if necessary, use iodine preparations, but only as prescribed by a doctor. ,  Results of studies carried out by the Office for sanitary inspection by the Food and Drug Administration (FDA), have shown that the iodine in the United States is mainly found in grain products, milk and cheese. 
Effect of iodine on pregnancy
Under the influence of iodine, the hormones thyroxine (T4) and triiodothyronine (T3) are synthesized, which play a huge role in the functioning of the endocrine, reproductive systems. Lack of iodine can lead to the following consequences:
- threatened abortion;
- mental retardation of the child;
- congenital pathology of the thyroid gland of the baby;
- metabolic disorders, overweight.
If the diet of pregnant women does not contain enough iodine, the fetus cannot produce enough thyroxin and its growth slows down. The fetus often dies in the womb, many children die within a week after birth. Modern data on brain embryology suggest that the critical time for the effect 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 form. It is also the time of snail formation (10–18 weeks), which also strongly influences the development of endemic cretinism. The 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 leads to neurological and psychological deficits in children. The  prevalence of attention deficit hyperactivity disorder is higher in children living in areas with iodine deficiency than in regions with a high iodine content.  The IQ of children living in iodine-deficient areas is on average 12.45 points lower than those living in areas with normal iodine intake. 
Having ascertained whether iodine is possible during pregnancy and its importance in its early stages, the question arises, does a growing organism need it in the third trimester? All the metabolic processes of the future child occur with the participation of the substance, so even if all the main organs are formed, iodine is necessary for their strengthening. , 
Iodine and folic acid during pregnancy
For the birth of a physically and mentally healthy child, in addition to iodine in the diet of a woman, vitamins, especially folic acid, play an equally important role. The latter is involved in cell division, the formation of a complete cardiovascular and nervous system, reduces the risk of termination of pregnancy, congenital defects of the child. In addition, it promotes the absorption of iodine. 
When planning pregnancy, even before conception, you need to take care to fill your diet with foods that are rich in B9: legumes, nuts, green salad, citrus fruits, and also take folic acid to meet the requirements of 400 μg per day when they try to get pregnant, and during the first 12 weeks of pregnancy when the baby develops the spine. 
If you have not taken folic acid supplements before becoming pregnant, you should start taking them as soon as you find out that you are pregnant. You can get them at pharmacies, large supermarkets, health food stores, or with a doctor’s prescription.
Similar actions with respect to iodine when planning pregnancy, but its thoughtless use is not always justified, because not all regions are deficient in the environment, for example, in the marine or oceanic coastal areas in abundance.
In any case, a microelement should be preceded by a visit to an endocrinologist, because there may be abnormalities in the thyroid gland, not related to pregnancy.
Does it make sense for men to take iodine during pregnancy planning? Most likely not, because stimulation of the functions of the corpus luteum, necessary for maintaining pregnancy in the early stages, placental transfer to the fetus at the embryonic stage, depends on the level of thyroid hormones of the mother.
Ways to saturate the body with iodine
In addition to food saturated with iodine, which was mentioned above, a special trace element enriched with trace elements (used to prepare dishes that do not undergo heat treatment, otherwise iodine will simply evaporate) can be used for various medical procedures, provided that there is no excess of it in the body:
- to gargle with iodine during pregnancy - many drugs are contraindicated for the treatment of angina, pharyngitis, laryngitis, oral diseases. In this case, a solution of iodine is able to act as an antiseptic and destroy pathogenic microbes. You can prepare it by boiling a glass of water, allowing it to cool to a warm state and dropping 2-3 drops of iodine there. In this case, 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, will soften the more aggressive action of iodine. The inflamed mucous will well perceive the alkaline solution, it will be easier to swallow;
- soda, salt and iodine - a classic rinse recipe that will cleanse the mucous membrane, soften it, show an antibacterial effect. A glass of water will need a spoonful of salt, the same amount of soda and 2 drops of the trace element. Do not exceed the recommended dose. It is best to rinse after eating, without increasing their frequency more than 3-4 times a day, so as not to dry the mucous membrane;
- Lugol's solution during pregnancy - they are smeared with inflamed tonsils, laryngeal walls. 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 their wounds, make iodine net in the field of bruises, injections;
- water with iodine - even iodized mineral water is released to overcome iodine deficiency. Its enrichment with a chemical element is carried out in accordance with the norms necessary for health. This is the most simple and affordable method of delivering a substance to the body;
- inhalations with iodine during pregnancy - a few drops of iodine in an inhalation solution will not only contribute to the treatment of colds of the upper respiratory tract, but also help to eliminate iodine deficiency in the body.
Iodine preparations during pregnancy
Many studies have established the benefits of iodine supplements during pregnancy in areas with severe iodine deficiency. ,
The endocrinologist, having conducted research on the state of the hormonal background of the woman, thyroid gland ultrasound, in order to avoid negative consequences for both pregnant and iodine deficiency children, may prescribe special drugs and advise how to take iodine during pregnancy:
- An iodine asset is a dietary food supplement, which is unique in its ability to be absorbed when there is a shortage of a substance and is simply removed from the body when it is abundant. In pregnancy, the recommended dose - 200mcg once a day during meals;
- Potassium iodine, a regulator of thyroxin 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 rate when carrying a fetus is 150-200mkg. The duration of treatment is determined by the attending physician;
- Candles Povidone-iodine - the drug has anti-pathogenic orientation. It is prescribed to eliminate vaginal infections. And although the instructions indicate one of the contraindications of pregnancy, it is used not only when planning it, but after conception.
Bacterial vaginosis, which women are often exposed to because of reduced immunity, can complicate a pregnancy and sometimes interrupt it. The doctor, weighing the risks of the disease and the danger of treatment, often makes a choice in favor of the latter.
In the first trimester, the treatment with povidone-iodine is the safest, in the second it is not used, a month before giving birth this becomes possible again, moreover, indefinitely. If a short course of therapy is sufficient, then there is nothing to fear at all.
According to NHANES, only 20.3% of pregnant women and 14.5% of lactating women in the United States take supplements containing iodine.  Currently, 114 out of 223 (51%) brands of prenatal and OTC prenatal multivitamins sold in the United States include iodine as a component, and many of those that contain iodine do not contain a labeled amount.  The US Women's, Infant, and Children's Nutrition Program recommended that all prenatal multivitamins given to women in this program contain 150 mcg of iodine per day, starting in 2010.
Substances that prevent iodine absorption
Competitive NIS inhibitors, such as perchlorate, thiocyanate and nitrate, can reduce the flow of iodine to the thyroid gland, thereby potentially aggravating the effects of iodine deficiency in the diet. Perchlorate comes from various sources, is extremely stable in the form of inorganic salt and persists in soil and groundwater for long periods.  In the United States, perchlorate has been found in many substances, including tobacco, alfalfa, tomatoes, cow's milk,  cucumbers, lettuce, soybeans, eggs, and multivitamins (including prenatal multivitamins). Thiocyanate, a metabolite of cyanide, which is produced as a by-product of cigarette smoke, and nitrate, which is produced naturally and is present in many finished products, can reduce the activity of NIS, thereby reducing the availability of iodine.
The levels of selenium and iodine in the urine in pregnant women are closely related.  Selenium is an important component of glutathione peroxidase and selonoproteins, which include 3 thyroid hormone deiodinases. Thus, the lack of selenium can lead to the accumulation of harmful peroxides in the thyroid gland and disrupt the process of peripheral deiodination, necessary for the production of the active thyroid hormone, T3 from T4. A recent study by Negro and his colleagues  reported that selenium supplements at a dose of 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 the supplement (20.3%) (p <0.01).
Harm of iodine during pregnancy
Despite the positive aspects of the effect of iodine on the health of women and the formation of a full-fledged person inside her, an overabundance of it carries no less damage than a deficit. This chemical is a toxic substance that can lead to:
- poisoning of the body;
- the development of thyrotoxicosis;
- dyspeptic disorders;
- muscle weakness;
- hair breakage;
- the formation of diffuse goiter;
- weight loss;
- threatened miscarriage;
- disruption of fetal development
Iodine load in the mother can potentially cause hypothyroidism in the fetus, but not in the mother. 
A new study warns that excessive exposure to iodine can also damage the health of the thyroid gland in the mother, and recommends a lower limit of iodine intake during pregnancy than that currently recommended by WHO and should be 250 mcg per day for pregnant women. The current recommended upper limits (TUL) for iodine intake throughout pregnancy are very different around the world. The TUL, set by the US Institute of Medicine, is 1,100 mcg per day,  which is more than 500 mcg per day, set by WHO and the European Food Safety Authority.
Excessive intake of iodine can cause changes in thyroid function in susceptible people . In normal people, a surplus of iodine can cause a temporary inhibition of the synthesis of thyroid hormone by a mechanism known as the acute Wolf-Chaikoff effect.  It has been established that an increase in iodine intake with food is associated with an increase in the prevalence of autoantibodies to the thyroid gland. 
An overdose of iodine during pregnancy can be expressed in its taste in the mouth. This can happen with long-term use of a microelement, in the case of multiple exceeding the recommended doses and simply with iodine intolerance during pregnancy.
Other signs of iodine intoxication are inflammation of the mucous membranes (conjunctivitis, rhinitis, bronchitis), digestive disorders, skin rashes, hoarseness, burning in the throat, and rapid breathing.
These manifestations are a sharp signal to consult a doctor.
Iodine for abortion
As you can see, iodine is not only a blessing, but it can also be evil. It is even used for termination of pregnancy in the early stages without the intervention of medicine. Is it so? In alternative medicine, recipes for milk with iodine and sugar with iodine are circulated, supposedly helping to get rid of unwanted pregnancy.
Since young people are now starting sex life early, still not fully aware of the intricacies of protection, there are often force majeure situations when you need to terminate a pregnancy before parents know about it. In the course begin to go various tips from the Internet.
In fact, there are no scientifically based arguments in favor of this theory. Doctors warn that drinking such a "remedy for pregnancy" can cause great harm to your body:
- cause bleeding;
- get a serious intoxication, including disability, and sometimes fatal;
- leaving a pregnancy after an unsuccessful attempt to give birth to a disabled child.
If in the recipe of milk with iodine the trace element will have a lower concentration, then dripping iodine onto sugar and taking it in general is dangerous.
Early termination of pregnancy can be accomplished by vacuum or medication, without giving yourself a great risk.