Their lungs may not ever reach their full capacity. Children with asthma are especially sensitive to secondhand smoke. It can actually increase the number and severity of asthma attacks, which may require trips to the hospital. Also, exposure to the smoke of as few as 10 cigarettes per day raises a child's chances of getting asthma even if that child has never had any symptoms. Inhaling smoke from the cigarettes of others is dangerous for pregnant women too.
Babies can have low birth weight that leads to many medical problems, and in some cases, death.
Pregnant women should stay away from smoke. It is one of the most important things you can do for the health of your children and the best way to prevent your child from being exposed to secondhand smoke. If you are having trouble quitting smoking, ask your doctor for help. As a parent, you are a role model. Children watch what their parents do.