Pneumonia occurs in the pregnant population with a frequency equal to that in the general population. However, its course is often more virulent, and mortality rates from certain pathogens may be high. The pregnant woman is more susceptible to injury to the respiratory tract due to a number of factors. These include alterations in the immune system which involve cell-mediated immunity and mechanical and anatomical changes involving the chest and abdominal cavities. The cumulative effect is decreased tolerance of hypoxia and acute changes in pulmonary mechanics. The spectrum of pathogens is similar to that for nonpregnant individuals, and the management of pneumonia in pregnancy does not differ in general from the nonpregnant state. However, careful attention should be paid to the fetoplacental unit with delivery generally indicated for obstetric purposes only. Issues that also need to be addressed include effects of certain infections, medications, fever, and hypoxia on the developing fetus.