Critical illness in obstetric patients requires a multidisciplinary approach given the complexity of treatment owing to pregnancy physiology and the need to manage both the maternal and fetal patient. Having an understanding of the physiologic changes in pregnancy, resulting pharmacokinetic and pharmacodynamic changes, and critical disease states specific to pregnancy, such as hypertensive disorders of pregnancy, obstetric hemorrhage, sepsis in pregnancy, amniotic fluid embolism, venous thromboembolism, acute fatty liver of pregnancy, and general acute respiratory failure in pregnancy, will allow for optimal management of an obstetric patient.