Sepsis accounts for approximately 10% of all maternal deaths. Pregnant women are susceptible to certain infections because of alterations in their cell-mediated immunity. Obstetric sepsis requires early broad-spectrum antibiotic therapy and may necessitate surgical intervention. Group A streptococcal infection may produce necrotizing fasciitis and toxic shock. Pyelonephritis remains a common cause of sepsis during pregnancy, and associated acute respiratory distress syndrome occurs more commonly than in the nonpregnant population. Severe pneumonitis caused by influenza virus and varicella zoster infection may occur. Malaria may be more severe in the pregnant woman, and carries significant risk to both mother and fetus.