Novel H1N1 virus infection and pregnancy.

Human infection with the novel H1N1 influenza virus, initially popularly termed "swine flu," was first reported in April 2009 and has since prompted the World Health Organization (WHO) to raise its pandemic alert to the highest level. During pregnancy both mother and baby are at increased risk when infected with either pandemic or seasonal influenza. Because of concerns about the severity of the disease during pregnancy, the Centers for Disease Control and Prevention (CDC) has implemented enhanced surveillance for infection with this novel virus in pregnant women and has placed them in a group that merits priority vaccine administration. The benefit of treatment with the antiviral medication oseltamivir outweighs its theoretical risk, as pregnant women are at increased risk of severe complications from H1N1 virus infection. In addition to confirmed H1N1 cases, the associated symptoms, particularly fever, merit immediate attention. Moreover, precautions must be taken by both patients and health care professionals when confirmed or suspected H1N1-infected pregnant women present to labor and delivery, or the doctor's office. After delivery, pregnant women infected with H1N1 may breastfeed but must follow specific guidelines. Although the current strain of H1N1 virus has fairly mild sequelae, the virus may have mutated over the summer months and we must anticipate a possible second wave of more severe illness moving into fall 2009 and winter 2010.