Common respiratory issues in ambulatory obstetrics. 
This article reviews the diagnosis and management of the most common respiratory conditions complicating pregnancy--asthma and influenza.  We also review strategies for smoking cessation in pregnancy as, in addition to exacerbating all other pulmonary conditions, smoking is the most modifiable risk factor for poor pregnancy outcome.  Moreover, the obstetrician frequently encounters each of these conditions in the ambulatory setting.  A thorough knowledge of the normal pregnancy-induced physiological respiratory changes combined with a comprehensive understanding of how to manage these conditions, will provide the obstetrician with the armamentarium needed to optimize health outcomes for mothers and their fetuses.