It can occur already in the pre-conceptional period (before conception) when one or both parents smoke, in the foetal period - when a pregnant woman smokes cigarettes or as a passive smoker inhales tobacco smoke from the environment, and after the birth of the child in a situation where household members smoke. In Poland, about 20% of pregnant women smoke cigarettes and almost half of children are exposed to passive inhalation of cigarette smoke. When a pregnant woman smokes, she introduces chemical compounds into her body, including carcinogenic substances, most of which cross the placenta and pose a threat to the foetus.

It is well known that smoking during pregnancy increases the risk of low birth weight. This situation is due to two mechanisms: it can be the result of a shortened duration of pregnancy or a reduction (slowing down) of fetal growth. The former situation results in the birth of a 'premature baby', while the latter results in the birth of a 'hypotrophic baby', i.e. a baby smaller than the duration of the pregnancy. Sometimes both mechanisms act simultaneously, resulting in the birth of a premature baby with symptoms of hypotrophy.

There is often media coverage of the serious consequences of prematurity, including persistent infections that require long-term antibiotic treatment. Less is said about the consequences of hypotrophy. Perhaps this is because, in general, babies born hypotrophic quickly compensate for their weight deficit and are seemingly no different from others.

However, as long-term epidemiological studies indicate, such children have an increased risk of type II diabetes (characteristic of adults), hypertension and ischaemic heart disease in adulthood. Rarely reported are the many complications of pregnancy resulting from smoking, such as miscarriages, placenta previa, premature separation of the placenta or rupture of the fetal bladder.