Smoking in pregnancy, the risks for the baby

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Philippe Gloaguen
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Smoking in pregnancy

Stop smoking during pregnancy it is an important thing to do, so as not to make the child take very serious risks. The toxic substances contained in cigarettes cross the placental barrier and cause damage to both the maternal and fetal organisms, increasing the risk of various problems. 

The risks of secondhand smoke in pregnancy

Is there smoke in the environment where the mother lives? Then there is smoke also in the environment of the fetus. Even if the future mother does not smoke, but she smokes those around her, the baby's body will be contaminated by secondhand smoke. If the future father does not smoke in front of his mother (or next to him) but far away, he will still expose her (and expose the fetus) to the toxins that remain on the skin and clothes. 

The benefits of a father who quits smoking do not stop only in pregnancy but also come after birth: the smoking of both parents increases the fact the risk of SIDS, white death of the newborn and other diseases and respiratory problems.

This applies not only to cigarettes, but also to cigars and pipes, which are potentially more dangerous than cigarettes because the smoke is not inhaled and is released in greater quantities into the air.

In this article

  • Cancer
  • Premature birth
  • Fetal death and cot death
  • Malformations
  • Growth disturbances
  • Lung problems
  • Future nicotine addiction
  • Damage to cells
  • Allergy
  • Behavior problems


If parents smoke they contribute to an increased risk for their children of getting sick cancer. Particularly frequent are the nose tumors. Children of mothers who smoked during pregnancy are also at a high risk of bladder and kidney cancer.

The frequency with which children of smoking parents are affected by malignant tumors was the subject of a study by the German Cancer Research Center. The researchers evaluated data from the Swedish Cancer Registry, which collects all cancers that have occurred in Swedish families over generations. The results are alarming: if the mother smokes the risk of getting cancer of the respiratory tract or bladder is one and a half times higher; for nose cancer the risk is nearly four times higher, for lung cancer 1,7 times. Bladder and kidneys they are particularly exposed to carcinogens in the growth phase, while the increased risk of nose cancer is attributed by researchers to secondhand smoke breathed in childhood.

Scientists also identified in the appearance of the lung cancer an indirect indicator of parental tobacco use and studied the children of about 18.000 mothers and 42.000 fathers affected by this disease, thus discovering that they had been registered as suffering from about 174.00 different forms of cancer, developed by the age of 70.

The children of the smoking fathers in this study they were looked at separately and it was found that if fathers have lung cancer, their children are at increased risk for nose and other cancers, but not for bladder and kidney cancer. .

By comparing with the percentages of oncological diseases developed by the children of non-smoking parents, the researchers were able to calculate the risks not attributable to the smoking habit of those affected or to heredity. It emerged that the carcinogenic effects on the bladder and kidneys would be independent of the father's relationship with smoking. Much more decisive seem to be the decomposition products of nicotine, which the child of a smoker receives when she is still in the belly or through the mother's milk.

Premature birth

One in seven babies of a smoking mother is born premature. In fact, smoking increases the risk of early birth by 6,7% (around 20%). 15% of premature births are attributable to the consumption of cigarettes during pregnancy.

Fetal death and cot death

If a pregnant woman smokes more than 20 cigarettes a day, the risk of a placental abruption, resulting in fetal death, is double that of non-smoking mothers.

According to estimates by the German Cancer Research Institute in Heidelberg about 25% of fetal deaths and 20% of white dead they could be avoided if women smokers managed to escape the addiction to smoking by the sixteenth week of gestation.

For mothers-to-be that they eliminate cigarettes during the first 13 weeksand the risk of fetal death or white death is about the same as that of mothers who have never smoked. However, this does not mean that smoking in the first trimester of pregnancy is not dangerous, since nicotine and many additives damage the development of organs especially in these weeks.

Read also: Pregnancy, 10 tips to say goodbye to cigarettes


The fetus is much more sensitive than the adult to the harmful effect of tobacco smoke, as its organs are still developing and are therefore not mature.

Detoxification from harmful substances is also more difficult, since the necessary enzyme systems in the fetus are not yet fully developed. If the fetus is forced to undergo passive smoking, malformations can then occur. The risk of cleft lip it doubles if a pregnant woman smokes one to ten cigarettes a day.

Growth disturbances

La nicotine reduces blood flow in the placenta. In this way, the tissues of the fetus are less perfused, resulting in growth retardation and poor weight gain.

The development in height in the children of smokers it is limited, the circumference of the skull reduced and the birth weight on average 200 grams less than normal.

Put simply: if a pregnant woman smokes one to five cigarettes a day, her birth weight is often less than normal by 150 grams; if the number of cigarettes is more than 20, the fewer grams can be 350. And low birth weight does not mean certainty of an easier birth. On the contrary, complications are even more frequent.

Lung problems

Tobacco smoke disturbs him pulmonary development of fetuses: lung function decreases if the mother smokes - a problem that often persists even after birth. Thus 28% of the affected fetuses in the first year of life develop at least one asthmatic disorder of the respiratory tract.

When exposed to tobacco smoke, fetuses, infants and young children suffer from chronic respiratory disorders, asthma, allergies and otitis media more frequently than children of non-smoking parents.

A future nicotine addiction

Children of smoking mothers have multiple nicotinic receptors in the brain. This makes them more prone to become heavy smokers in their turn if in adolescence they decide to try the "road "nicotina.

Babies of mothers who smoke after delivery must be detoxified

Damage to cells

Many harmful substances found in tobacco smoke cross the placenta and end up in the blood circulation of the child. This is the case, for example, of the carbon monoxide, which blocks the transport of oxygen in the blood and thus puts the oxygen supply to the fetus at risk.

In the same way, carcinogenic substances such as polycyclic aromatic hydrocarbons and nitrosamine, specific to tobacco, all capable of damaging the genetic heritage. And because the body of a fetus has a higher metabolism than that of an adult, the risk of becoming addicted to the harmful substances in tobacco smoke is greater.

In addition, children take more breaths per unit of time than adults and have a higher respiratory volume for each kilogram of body weight. As a result, they breathe more poisonous substances than their body weight.


Il smoking promotes allergies - and this even for several generations. The grandchildren of a grandmother who smokes are at a higher risk of developing allergies than children with a smoking-free family tree, as Professor John Warner of the British University of Southampton has pointed out.

Together with his colleagues he interviewed the parents of 908 children and analyzing the answers revealed that the grandchildren were burdened by smoking even though we had never had contact with smoking grandparents.

"If a pregnant woman smokes, it probably damages the genetic makeup of the eggs in the female fetus"

Warner says. And from these damaged eggs are born the grandchildren with a high predisposition to allergies.

Behavior problems

In addition to the effects on physical development, smoking is thought to also cause psychic problems.

From the Mannheim "Zappelphilipp studie", a prospective longitudinal study on 362 children, conducted by doctors of the Mannheim Institute for Psychic Health, it emerged that the children of smoking mothers, subjected to periodic examinations from birth until the beginning of adolescence, they achieved worse school results and showed character disorders with a frequency two to three times higher than the children of non-smoking mothers. Compared to the latter, the level of inattention, impulsivity and hyperactivity was also much higher. The Mannheim doctors therefore advanced the hypothesis that during pregnancy there is a risk factor for a subsequent disturbance in the attention of the child.

Nicotine damages the receptors in the still developing brain of the fetus, with a consequent risk of ADHD (Attention Attention and Hyperactivity Syndrome).


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