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Intoxicants and medication

The use of intoxicants should be stopped as soon as you start planning a pregnancy. Women who smoke or consume a lot of alcohol will take longer to get pregnant and have a higher risk of miscarriage. This page contains information on different intoxicants and their effects on a child’s development.

Unnecessary use of medication should also be avoided during pregnancy and when planning a pregnancy. However, the foetus’ well-being depends on the mother’s well-being, so the use of important medication must not be discontinued. You should always tell your doctor if you are planning to become pregnant, so that your medication can be adjusted to be as safe as possible for the foetus, even before pregnancy. More detailed information on harmful medicinal substances at HUS's website.


Tobacco is a stimulant that causes dependence either as a habit or through the even more severe nicotine addiction. Tobacco influences the central nervous system in two ways, both stimulating and calming it. Tobacco smoke contains around 4,000 substances, 50 of which cause cancer. Most of these chemical components travel through the placenta and umbilical cord to the baby growing in the womb. (More information)

Passive smoking – staying in the same premises with people who are smoking – is equally harmful both to the mother’s and the child’s health. Nicotine contracts the walls of the womb, placenta and umbilical veins. The contracting blood vessels cause an immediate lack of oxygen for the baby in the womb. Nicotine does not exit the baby’s system as quickly as the mother’s. Researchers have taken blood samples of the child’s umbilical cord during birth, and these samples have shown higher content of nicotine than in the mother’s blood.

In addition to causing lack of oxygen, nicotine has other impacts on the child. It hinders the development of a child’s nervous system and brains. Among other issues, nicotine slows down the division of brain cells. Carbon monoxide is easier bound to the blood’s haemoglobin. Haemoglobin carries oxygen for the cells, so this decreases the oxygen flow to tissues and cells. In addition to carbon monoxide and nicotine, tobacco smoke also contains cyanide, which is a cytotoxin, and the heavy metals cadmium and lead.

Tobacco’s effects on the baby

A baby exposed to tobacco smoke in the womb is born lighter than other children, even in full-term pregnancies. Smoking also increases the risk of premature birth. A baby, who is used to tobacco, will suffer from nicotine withdrawal symptoms: the baby is irritated, cries more and is restless. He or she will need more care than usual, but may still remain irritated despite all the love and care. A child, who has been exposed to tobacco smoke later in life has a bigger risk of respiratory tract infections and asthma than other children. Additionally, if a child suffers from learning disabilities or difficulties with concentration, the cause for this can be exposure to smoking during pregnancy.

Cigarette smoke is carried to breast milk. Smoking decreases the amount of breast milk by up to 30%. The fat and nutrient contents of the milk decrease, too. Despite this, breast milk, nursing and skin contact are important both to the new-born baby and the mother.

It is always beneficial to quit smoking. For many future parents, pregnancy is a great motivator for reducing or quitting smoking. Quitting is difficult, but help is available. Various groups can provide support and health stations, for example, arrange detoxification courses free of charge. You should discuss quitting smoking and the different forms of treatment at the maternity clinic.


It is difficult to determine safe limits for alcohol use during pregnancy. A small amount of alcohol does not cause a risk of deformity, but the limit for alcohol use causing malfunctions of the central nervous system is unknown. This is why alcohol should not be consumed during pregnancy. The alcohol use of the expectant mother and her spouse is assessed at the maternity clinic with the help of extended substance use survey (pdf), which you can read through at home (More information)

Alcohol penetrates the placenta easily. It travels to the tissues of the baby growing and developing in the womb and accumulates in organs with high liquid content, such as the brain. The alcohol leaves the child’s system through urine and via the skin and lungs, into the amniotic fluid. A baby in the womb swallows the amniotic fluid from time to time, which means that the alcohol travels back into their system. Alcohol exits the amniotic fluid slower than the blood stream of the mother and the baby. That is why the alcohol content in the amniotic fluid may be higher than the content measured from blood samples. The liver of an unborn baby cannot process alcohol like an adult’s liver and the even liver of a new-born baby can only process alcohol at about half the rate of an adult’s liver. Eventually, alcohol travels through the placenta into the mother, whose liver will finally process it.

The most vulnerable times for a baby growing in a womb are the first 24 weeks of pregnancy, during which the baby’s organs develop. Heavy use of alcohol during pregnancy increases the risk of haemorrhages and premature birth. It also affects the placenta and may facilitate its premature expulsion.

The most severe possible handicap caused by alcohol use during pregnancy is the only preventable developmental disability, i.e. FAS (foetal alcohol syndrome) (Terveyskirjasto, in Finnish). The symptoms vary in accordance with the syndrome's degree of difficulty from a severe disability to mild behavioural problems and difficulties with concentration.

Alcohol also travels through to breast milk. The breast milk’s alcohol content is the same as in the mother’s blood. Alcohol exits the milk at the same rate as it exits the blood stream, which means that it takes two hours for one alcohol serving to exit the mother’s system. Nursing is not recommended as long as there is alcohol in the mother’s blood stream, even if the child does not get drunk on such small amount. The child can sense the mother’s changed behaviour – her louder voice and the clumsier, rougher touches – and starts to feel restless and insecure.


Various narcotics and drugs penetrate the placenta easily. The effects of smoked drugs on the mother and the child are similar to those of tobacco, although partly more severe. THC, i.e. tetrahydrocannabinol, which is the active substance in cannabis, carries over to breast milk. (More information)

Intravenous drugs, or drugs that are breathed in or consumed as pills or powders cause the child various heart defects, even cardiac arrests, as well as lack of oxygen, undernourishment, developmental defects of the brain and urinary tract, mental retardation and eye defects. The withdrawal symptoms of a new-born can be severe, last a long time and also be delayed. All these drugs are absorbed into breast milk, so nursing is not recommended for drug users.

Most medications, too, penetrate through the placenta and enter the child’s system through it or through breast milk during nursing. The attending doctor should always be notified of the pregnancy and nursing, so that the doctor can choose the safest treatment option for the mother and the baby. Use of non-prescribed medication should be avoided.



02.11.2020 10:08