MODEL RELEASED. Asthmatic pregnant woman. Woman using an aerosol inhaler to control her asthma. The inhaler releases a drug called salbutamol which dilates the bronchial muscles, allowing air to pass into the lungs. The use of salbutamol for normal asthma control does not harm a pregnant woman or her baby. Nearer to birth, the large doses of salbutamol used in an asthma emergency can slow or prevent birth. Salbutamol has been used specifically to delay birth in some cases.