smoking during pregnancy is not safe for the fetus and pregnant women must avoid smoking. In a single cigarette, more than four thousand components are present. Lead, tar, carbon monoxide and carcinogens are some of the common components and all these may cause respiratory issue in the fetus. How smoking during pregnancy effects? It affects by halting the normal supply of oxygen and the blood to the baby via placenta. What are the effects of smoking during pregnancy? It causes constriction in the blood vessels which in turn may lead to restricted supply of nutrients to baby. Under such condition, expecting mother will give birth to low birth weight baby. Such babies are more prone to the chronic diseases.