Table 6.

Alterations in pregnancy predisposing to an increased incidence and mortality from pneumonia

Immunologic changes Reduced lymphocyte proliferative response Diminished cell-mediated cytotoxicity Reduced number of helper T cells Reduced lymphokine response to alloantigens

Hormonal changes Elevation of progesterone, human chorionic gonadotropin, alpha fetoprotein, and cortisol may also inhibit cell-mediated immune function

Physiologic changes Increase in oxygen consumption Increase in lung water Elevation of diaphragm Aspiration more likely in labor and delivery