Safety of neuraminidase inhibitors against novel influenza A (H1N1) in pregnant and breastfeeding women.

A new strain of influenza A virus (novel influenza A H1N1) that originated in swine has rapid ly spread from the initial outbreak in Mexico and the southern United States to Canada and many countries in Eu-1 Because many infected people are young, 2 the care of pregnant and lactating women is a concern. 3–6 According to the US Centers for Disease Control and Prevention , the novel H1N1 influenza virus is susceptible to os-eltamivir and zanamivir, neuraminidase-inhibitor antiviral medications, which target the early phase of the infection. However, this strain is resistant to adamantanes, such as amantadine and rimantadine. 7 The Centers for Disease Control and Prevention currently recommend antiviral treatment and chemoprophylaxis with either oseltamivir or zanamivir against novel H1N1 influenza for people at high risk of complications , including pregnant women. In this report, we summarize information about the safety of neuraminidase inhibitors for treatment of novel H1N1 influenza in pregnant and breastfeeding women. Although the information about drug safety in this report is also applicable to seasonal influenza and future pandemics, the management strategy presented in this article is specific to novel H1N1 influenza. Evidence We performed a literature search to identify reports of the use of oseltamivir or zanamivir during pregnancy, lactation and breastfeeding using MEDLINE Relevant information was also gathered through the network of teratogen information services in Japan, where the use of oseltamivir and zanamivir for patients with confirmed influenza was relatively common even before the current pandemic. Pregnancy Little is known about whether influenza viruses are transmitted to the fetus through the placenta, although this class of viruses is not considered to be teratogenic in humans. Ács and colleagues 10 suggested indirect teratogenic effects of maternal influenza during pregnancy, possibly because of high fever, based on 1 case-control study and the known effects of hyper-thermia, which is associated with an increased incidence of neural tube defects. especially in the third trimester, than among nonpregnant and postpartum women. 12 This is consistent with increased mortality among pregnant women during past influenza pandemics. Although the novel H1N1 influenza virus may not be as virulent as anticipated, the increased risk of complications during pregnancy should be taken into account when caring for affected patients. According to the Centers for Disease Control and Prevention, 20 recent infections of novel H1N1 influenza in the United States (15 confirmed and 5 probable) were in pregnant Key points • …