Various physiological changes occur as a result of the pregnant state, affecting patients with pre-existing lung disease and affecting the assessment and management of the patient with respiratory failure. Asthma, pulmonary infections, tuberculosis are some of the conditions not specific to pregnancy. Acute severe asthma in pregnancy may be treated as in the non-pregnant patient with intravenous beta- 2-adrenergic agonists, intravenous theophylline, intravenous magnesium sulfate and steroids. Standard drug therapy, namely with isoniazid, rifampin, and ethambutol has an acceptable safety profile in pregnancy and is recommended for pregnant women by the US Centers for Disease Control and Prevention and the American Thoracic Society. Acute respiratory distress syndrome (ARDS) occurs fairly frequently in pregnancy and is a leading cause of maternal death. Several approaches to respiratory support, including conventional mechanical ventilation, airway pressure release ventilation, high-frequency oscillation, and extracorporeal membrane oxygenation, have been used successfully in pregnancy.