Abstract

Influenza is a highly contagious acute respiratory infection that is of major clinical importance both in Japan and worldwide. This infection usually is not life-threatening in otherwise healthy adults, but pregnant women do not tolerate serious pulmonary involvement. In previous reports of influenza pandemics, pregnant women have experienced increased risk of morbidity and mortality compared to non-pregnant women. In addition, mothers with severe respiratory infections may have an increased risk of preterm labor. Vaccination against influenza is recommended for all women who will be pregnant during the influenza season to prevent the occurrence of influenza and the development of pneumonia. There is no firm evidence that maternal infection is associated with an increased risk of spontaneous abortion, stillbirth, or congenital anomalies. However, an infant delivered to an acutely infected patient may develop neonatal influenza as a result of close personal contact with its mother.