How did asthma developed? and is this will affect my pregnancy?or for the baby? how did asthma developed? and is this will affect my pregnancy?or the baby?

Asthma : Asthma is caused by over-reactive airways in the lung. There is sometimes a family history. Asthma can be worsened by air pollution or smoke exposure. Although asthma can run in families, your baby will have only half of your genetics so may not get asthma. Your asthma is extremely unlikely to affect your baby as long as you keep your asthma under control. Be sure your doctor is aware if you have asthma symptoms.