Other exposures

For a substance to have an impact on fetal development or to be excreted into breast milk, it must first be present in the mother’s bloodstream. The rate of absorption of hair dyes from the scalp to the circulation depends on the state of the skin (absorption may be higher if the skin is broken), the area over which the dye is spread (the larger the area, the greater the absorption), the time you allow the dye to take effect (the longer you leave the dye in, the greater the absorption), and how often you dye your hair (the more often, the greater the exposure).  

When creating highlights, the dye is usually not in direct contact with the scalp and, therefore, cannot be absorbed into the bloodstream as much. Thus, highlights are a better alternative than dyeing all of your hair during pregnancy and breastfeeding. Nothing is absorbed into the bloodstream through the hair, so if you already have dyed hair, this presents no risk for pregnancy or breastfeeding.

Hair dyes contain a large number of different chemicals, and little studies have been conducted on their effects on pregnancy. In addition, even severe allergic reactions are possible. The most common allergenic substance in permanent and light hair dyes is paraphenylenediamine (PPD). But because the safety information available on hair dyes is limited and because the purpose of dyeing your hair is a purely cosmetic one, you should perhaps avoid dyeing your hair during pregnancy.

If you have dyed your hair while pregnant, there is no need for concern and no need to take any action. But because the safety information available is limited and because the purpose of dyeing your hair is a purely cosmetic one, you should perhaps avoid dyeing your hair during pregnancy. There are no official recommendations as to how many times it is permissible to dye your hair during pregnancy. However, all unnecessary exposure during pregnancy should be avoided. 

If you have dyed your hair during breastfeeding, you do not need to take a break from breastfeeding. However, you should avoid repeatedly dyeing your hair also during breastfeeding. 

In its evaluations in 2021, the EU’s Scientific Committee on Consumer Safety has concluded in its opinion that the use of natural henna (powder made from the leaves of the Lawsonia inermis plant) is safe. Natural henna contains on average approximately 1% of lawsone (hennotannic acid) and its safe limit is set at 1.4% in the product (https://health.ec.europa.eu/). The safety of lawsone concentrations higher than this has not been evaluated. Pure natural henna rarely causes allergic symptoms.

Lawsone can also be produced synthetically. However, the concentrations in the products can then be significantly higher than in natural henna. Dyes containing synthetic lawsone should not be used during pregnancy and breastfeeding.

The so-called “black henna”' contains PPD. Even severe allergic reactions are possible. Products containing black henna must not be used during pregnancy and breastfeeding.

• Primarily wear protective clothing and apply a repellant such as citronella oil to your clothes as necessary. Citronella oil repels mosquitoes, but it has a low impact and short duration.
• You may burn mosquito coils outdoors. 
• Electric insect repellent devices generally contain allethrin. There is no research available on allethrin use during pregnancy. We do not recommend staying in a room while an electric insect repellent device is switched on; do not enter the room until the device has been switched off. 

Chemical insect repellents spread on the skin, such as products containing diethyltoluamide (DEET), are not recommended during pregnancy. Considerable amounts of active agent may enter the body through the skin from insect repellents. There is no research available on the excretion of DEET into breast milk. It is likely that if insect repellent is used on small areas, the levels of DEET excreted into breast milk will not be significant. Please be careful not to bring the infant into direct contact with the substance. Only apply insect repellent to skin areas that you cannot cover with clothing.  

If you have an itchy and irritated insect sting, it is safe to apply topical skin creams (e.g. hydrocortisone or dexpanthenol). In case of an emergency because of a sudden and severe allergic reaction (e.g. due to a wasp sting), you may use an epipen (adrenalin shot).

If you discover a tick bite on your body while you a are pregnant, always contact a physician for evaluating the need for treatment. 

Avoid travel to risk areas for diseases such as malaria, Zika virus, dengue fever and West Nile virus during pregnancy and even before, when planning the pregnancy. These diseases, transmitted by mosquitoes in those areas, pose significant risks during pregnancy. If, however, it is essential for you to travel to a risk area, please protect yourself carefully with clothing, mosquito nets and chemical mosquito repellents.

• Among chemical mosquito repellents, we recommend those containing diethyltoluamide (DEET), because they are the most effective. However, limit their application to skin areas that remain uncovered by clothing, and observe the doses specified in the package. 
• Wash the substance off your skin as soon as there is no risk of a mosquito bite. 
• Do not apply the product if the skin is broken. 
• Wash your hands carefully after applying the product.  
• Chemical mosquito repellents may compromise the effectiveness of sunscreen. 
• Apply the sunscreen first and the mosquito repellent last so as to gain the best possible protection.

Insecticides are safe for humans if used properly. Most of the active agents used are pyrethrins or pyrethroids. Although these substances have not been found to be harmful for the fetus, you should avoid undue exposure during pregnancy. When using insecticides, follow the manufacturer’s instructions and withholding period. If possible, ventilate the space after applying insecticide.

You should favor sunscreen where the protection is based on a physical barrier (titanium oxide or zinc oxide). Also remember to wear protective clothing. Avoid frequent use of chemical sunscreen, because various substances may be absorbed through the skin, particularly if applying the sunscreen to large areas of skin. Some of the substances used in sunscreens have been shown in laboratory conditions to act similarly to estrogen (e.g. octyl methoxycinnamate, OMC). Day creams and foundations may also contain chemical protective agents, so you should avoid continuous use of these as well. 

Avoid self tanning skin creams. These products contain dihydroxyacetone (DHA). While this substance does occur naturally in plants, animals, and humans as a product of sugar metabolism, its potential impacts on fetal development have not been studied. The products may also contain other substances whose impact on fetuses has not been studied. Thus, it is best to avoid applying these products repeatedly on large areas of skin. 

Avoid continuous use of perfumes. Perfumes may contain substances that act like estrogen. We do not recommend the use of any perfumes, aromatherapy oils, or other strongly scented products during pregnancy. 

You may use deodorants, even ones containing aluminum, during pregnancy and breastfeeding. The product is only intended to be applied in a small area, and absorption through the skin is minimal. 

Toothpastes are safe. Tooth whitening products available in supermarkets are also permissible. 

You may use mouthwashes during pregnancy and breastfeeding. Any alcohol that the product may contain is not a problem in normal use, as long as you do not swallow the mouthwash or keep it in your mouth for long periods of time. However, mouthwashes containing iodine, such as Betadine, are not recommended.

We do not recommend repeated applying of artificial nails during pregnancy. If you already have artificial nails, these do not represent a risk, and you do not need to remove them during pregnancy. If you are pregnant and your job involves applying artificial nails, please consult your occupational health care service to review the recommended protective measures. 

Eyelash extensions are affixed with glue that contains acrylate compounds dissolved in solvents. Although the quantity of glue used is minimal, levels of substances in the air at the service location may be elevated during the procedure, so you may be exposed to solvents for up to two hours. Also, acrylate compounds are common allergens, and you may experience local allergic reactions. For these reasons, we do not recommend getting eyelash extensions during pregnancy or breastfeeding. If your job involves performing these procedures, please review the recommended protective measures on the website of the Finnish Institute of Occupational Health (www.ttl.fi ). 

Tattooing involves injecting a dye into the lower layers of the skin (dermis) using a hypodermic needle. The dye will remain in the skin for a very long time, up to decades, but some of the dye may be leached into the body. There are no research findings concerning the safety of tattoo dyes during pregnancy. For this reason, we do not recommend getting a tattoo during pregnancy.  

This also applies to microblading, even though in that process the dye is only injected into the surface layer of the skin. These procedures involve a risk of infection and allergic reaction, and pregnancy may actually influence this. We recommend that you do not have such procedures performed until you have finished breastfeeding. 

It is advisable to ensure that the vaccinations needed for traveling are up-to-date well in advance, and to try and have them administered before becoming pregnant, if you know you are going to travel. However, routine vaccination/boosters included in the vaccination program are not recommended to be taken during pregnancy without a specific reason. Vaccines that do not contain live pathogens may, at the health professional’s discretion, be administered if a pregnant person will be traveling to a high-risk area.

For more information on vaccinations during pregnancy (THL)

During pregnancy, vaccines can be given at a professional’s individual discretion to those who will be staying in a high-risk area for more than a month. 

In addition to tick-borne encephalitis, the ticks spread borrelia, against which there is no vaccine. If you are pregnant and you are bitten by a tick, always consult a physician.

The risk of severe malaria is high in pregnant women, so traveling to an area where malaria has been observed should be avoided during pregnancy. Malaria can cause severe anemia and increase the risk of miscarriage. Fetal growth may also slow down and the risk of low birthweight and fetal death increases. A malaria infection during pregnancy can cause the placenta to rupture and induce premature labor. 

Prophylactic medications do not yield complete protection, and wearing protective clothing is therefore essential. It is advisable to discuss suitable prophylaxis options with your physician if travel is necessary. Remember to use mosquito nets and repellents.

See more information on malaria

The Zika virus belongs to the flavivirus group. It generally only causes a mild fever, but it can be dangerous for the fetus. The Zika virus is endemic in Africa, India, Southeast Asia, and South America. The Zika virus is principally transmitted by mosquitoes that are active in the daytime. A Zika virus infection during pregnancy may cause microcephalia and other damage to the central nervous system in the fetus. Microcephalia is a condition where the head of the fetus does not grow as large as normal, and this may compromise the development of the brain. In the worst cases, the result may be a severe developmental disability.
 
A trip to a Zika region should be avoided if pregnancy is possible or you are already pregnant. The authorities stress the importance of prevention if it is not possible to avoid traveling to the region. Avoid mosquito stings by dressing in clothing providing good coverage, avoiding places where mosquitoes appear, and using mosquito nets when sleeping. 

Other mosquito-borne infections include dengue and yellow fever, Japanese encephalitis, and West Nile virus. Although these are not known to be directly harmful to the fetus, the mother’s serious viral infection as such is also a risk for the fetus. Traveling to risk areas should be avoided during pregnancy. Vaccination of a pregnant person against yellow fever may be considered in situations where travel is necessary. There is no vaccine for dengue fever. There is a vaccine against Japanese encephalitis that can be taken if there is a clear reason, such as, if you are staying in rural conditions for more than a month.

It is advisable to protect yourself from mosquito bites primarily with adequate clothing and by sleeping under a mosquito net at night. Mosquito repellents can be used in areas that cannot be covered by clothing. It is worth trying to avoid places where there are mosquitoes. When you’re outside, you can burn mosquito repellent spirals. 

The most effective chemical mosquito repellent is DEET (diethyltoluamide). Its use during pregnancy is justified if you travel to an area where there is a risk of serious infection (for example, malaria or the Zika virus is present in the area). Since DEET is absorbed from the skin into the bloodstream, it is advisable to limit the use of the repellent to skin areas not unprotected by clothing. The effectiveness of other mosquito repellents applied on the skin is lower.

Good hand hygiene is of utmost importance. Wash your hands with soap and always use hand sanitizer before eating. You can also use a lactobacillus product during the journey. Diarrhea is primarily treated with good hydration and oral rehydration solutions that maintain the body’s electrolyte balance. Afebrile diarrhea can also be treated with short-term use of loperamide preparations in difficult situations. If diarrhea persists, it is advisable to consult a physician who will prescribe a course of antibiotics if necessary.

When traveling, you should only eat well-cooked meat, fish, or chicken. Lettuce, fruit and vegetables should be washed thoroughly or peeled. For example, raw meat, vegetables or lettuce with soil may contain pathogens that can be dangerous for pregnancy and the fetus (Toxoplasma, listeria).

Pregnancy increases the risk of blood clots associated with long flights even further. Long flights should therefore be avoided at least during the last month of pregnancy and short domestic flights for the last two weeks. It is worth checking the potential risks associated with pregnancy, for example, by asking at the maternity clinic. Certain airlines may require a medical certificate from pregnant passengers before the flight. For more detailed instructions, refer to your airline’s website.

The amount of cosmic radiation from a single flight does not pose a risk to the fetus. If hundreds of flight hours are accumulated during pregnancy, flying should be limited on a case-by-case basis due to cosmic background radiation exposure.

You should not dive while pregnant. When diving, the supply of oxygen can be disturbed and the potentially developing gas bubbles can be dangerous for the fetus. Pregnancy and diving do not mix.

Protecting yourself with clothes is a top priority. During pregnancy, you should select a sunscreen that offers physical protection (e.g. titanium dioxide). At least some of the chemical sunscreens are absorbed through the skin so that these substances are measurable in the bloodstream. The potential effects on fetal development are not known in detail. Therefore, the use of products containing chemical sunscreens repeatedly or on large areas of skin should be avoided.   

During pregnancy, the aim is to avoid any unnecessary X-ray examinations. However, situations may arise during pregnancy when an X-ray examination is necessary. For example, the amount of radiation from dental X-rays is so small that it will not harm the fetus, and an imaging procedure can be done if there is a clear indication for it. From dental X-rays, the radiation dose received by the fetus is less than 0.01 millisieverts, even when the mother does not receive abdominal protection. Doses below 50 millisieverts do not increase the risk of fetal malformations or central nervous system damage.

More information on X-ray examinations can be found on the website of Radiation and Nuclear Safety Authority (STUK).

If you are pregnant and occupational exposure is considered harmful, you should be transferred to work duties where harmful exposure does not occur. If there is no such possibility, you may possibly be granted special maternity leave.

Occupational health care has a statutory duty of surveying the working conditions of pregnant employees. If you do not have access to occupational health care, you can primarily consult your health center physician. If necessary, the physician may also consult experts from the Finnish Institute of Occupational Health. You can also fill in the Pregnancy and Work data collection form on the website of the Finnish Institute of Occupational Health, for asking for information on harmful exposures from the experts at the Finnish Institute of Occupational Health.

Vitamin A is a fat-soluble vitamin that regulates the growth and differentiation of rapidly growing cells in particular. The function of vitamin A is, among other things, to take care of the functioning and regeneration of the skin and mucous membranes, as well as to promote bone growth. In addition, it affects vision, the development of immune response, as well as reproduction.

• The most common form of vitamin A is retinol that comes from animal sources.
• The consumption of foods rich in vitamin A should be restricted during pregnancy. You can read about the food recommendations during pregnancy on the Finnish Food Authority’s website.
• There is no need for vitamin A supplementation during pregnancy, as a normal Finnish diet usually provides a sufficient amount of vitamin A.
• The most common multivitamin preparations, which can be purchased in Finnish pharmacies, do not contain vitamin A in amounts that would damage the fetus.
• Remarkably high doses (> 7,500 micrograms/ 25,000 IU) of vitamin A may be harmful to the development of the fetus.
• Beta-carotene is a precursor of vitamin A found in plants. The beta-carotene that comes from food cannot provide a harmful amount of vitamin A. However, food supplements containing beta-carotene should not be consumed during pregnancy.

Intake recommendations

 Recommended daily dietary intake of vitamin A:

• During pregnancy, the recommended amount is 800 micrograms (2,700 IU) per day.
• During breastfeeding, the recommended amount is 1,100 micrograms (3,300 IU) per day. The vitamin A contained in breast milk is enough to meet the infant’s vitamin A needs.

Vitamin D is a fat-soluble vitamin needed for the absorption of calcium and phosphate and for the development of the fetal skeleton. Vitamin D deficiency causes bone growth and development disorders, such as rickets in children and skeletal mineralization disorder (osteomalacia) and osteoporosis in adults. 

• During pregnancy, the recommended intake of vitamin D is 10 micrograms per day for all pregnant people throughout the year, regardless of their diet.
• Primarily, vitamin D is recommended to be taken in the form of D3.
• There is little information on the effects of high doses of vitamin D on pregnancy. If a significantly higher dose (e.g. 50 or 100 mcg/day) has been used in early pregnancy, there is no evidence that is would cause any particular risk. However, the dose of vitamin D should be dropped to the recommended level for the remainder of the pregnancy, unless otherwise instructed by your physician.
• During breastfeeding, the recommended intake for the mother is 10 micrograms per day. Breast milk contains only little vitamin D, which is why it is important to give the child vitamin D supplements. However, the intake recommendations should not be exceeded as there is no information on how higher doses affect the vitamin D content of breast milk. 

Vitamin D sources in nutrition

The main sources of vitamin D in nutrition are fish, meat, egg, vitaminized dairy products, and margarine. The use of foods with added vitamin D is safe during pregnancy. You cannot get too much vitamin D from normal food or sunlight.

The recommended daily intake of iodine during pregnancy is 175 micrograms per day. The iodine intake of Finns is gradually improving as a result of the recommendation to use iodized salt (FinRavintotutkimus 2017, THL). 

During pregnancy, adequate iodine intake is also important for the fetus's development and thyroid function. Insufficient intake of iodine can have a detrimental effect on intellectual development. 

Sources of iodine from food include meat, fish, eggs, and dairy products. Although the use of salt should not be increased, it is important to use iodized table salt as the salt in your diet. Adequate iodine intake can be ensured already when planning pregnancy by using multivitamin products from the pharmacy intended for use during pregnancy. They contain between 100 and 175 micrograms of iodine per daily dose, thereby ensuring an adequate daily intake of iodine.

Food supplements containing seaweed can contain large amounts of iodine and their use during pregnancy is not recommended.

During breastfeeding, the recommended daily intake is 200 micrograms.

People who have a thyroid disease should discuss the iodine dosage with a physician.

Iron is an important component of red blood cell hemoglobin, and its function is to carry oxygen from the lungs to the tissues. The need for iron in women of childbearing age varies individually. The increased need for iron during pregnancy is due to an increase in the amount of blood, the placenta, and the growth of the fetus. The S-ferritin value reflects the amount of stored iron. Iron deficiency can cause fatigue, poor physical condition, and anemia.  

Intake recommendations

• An ordinary diet can satisfy about half of the iron needed during pregnancy, and the other half must be obtained from the mother’s iron stores or iron supplements.
• During pregnancy, hemoglobin values are monitored in the maternity clinic and intake of iron supplements can be started according to the instructions of the maternity clinic.
• During pregnancy, iron deficiency is primarily treated with oral iron supplements, usually from 100 to 200 mg per day.
• The use of iron supplements in early pregnancy does not increase the risk of fetal damage, but it can increase potential nausea in early pregnancy.
• The decision on intravenous iron infusion must be made in specialised medical care. Iron infusion is associated with a risk of a severe allergic reaction and it should always be assessed carefully by the attending physician. 

Iron-rich herbal juices are available in pharmacies and natural health product stores in Finland. In addition to iron and water-soluble vitamins, some products contain small amounts of several different fruit juices and herbal extracts. The amount of iron in these products is generally not sufficient to ensure iron intake during pregnancy, and there is insufficient scientific evidence of safety of all herbal extracts during pregnancy.

Iron absorption is impaired by calcium and antacids (calcium, magnesium and aluminum salts) used to treat heartburn, among others. Iron supplements inhibit the absorption of thyroxine and there should be a break of at least four hours between taking them.

Sources of iron in nutrition

In food, iron occurs in two forms, in animal products mainly as heme iron and in plant products as non-heme iron. Heme iron of animal origin is absorbed more efficiently in the intestine than iron of plant origin. Iron is obtained from meat, organ meat or offal, and wholegrains, especially rye bread.

The absorption of iron is facilitated by the simultaneous consumption of vegetables, berries and fruits rich in vitamin C. But tea, coffee and dairy products prevent the absorption of iron.