Carbon monoxide and nicotine in tobacco both reach the baby very easily through the placenta . Both of these can cause problems with the baby's growth and development before birth. Carbon monoxide and Nicotine reduce the amount of oxygen available in the mother's blood, which can affect the development and size of the baby. Smoking can cause problems in pregnancy such as miscarriage , stillbirth , placental problems , bleeding during pregnancy and premature birth .
Babies practise breathing movements while in the womb.
It has been shown that cigarette smoking can disrupt these breathing movements. Research has also shown that babies of smokers are generally below the average birth weight and that these babies can develop complications such as infections and breathing problems during the first weeks of life. Some research has indicated that smoking may increase the risk of cot death . It can accumulate in the amniotic fluid surrounding the baby before the birth and cause problems such as miscarriage , stillbirth , bleeding during pregnancy and premature birth . There is evidence to suggest that if a woman drinks two or more standard drinks each day the baby can be affected and grow slowly.