Maternal and Neonatal Outcomes After Antepartum Treatment of Influenza With Antiviral Medications

Abstract

Pregnant women are at increased risk of severe morbidity and mortality, secondary to influenza infection. Vaccination programs are the cornerstone of influenza preventive efforts and when they fail, 2 classes of antiviral drugs are important for both postexposure prophylaxis and treatment. The first class, the M2 ion channel inhibitors, includes amantadine and rimantadine, and is effective for the prophylaxis and treatment of influenza A. The second class, the neuraminidase inhibitors, includes oseltamivir, which is effective against both influenza A (including novel H1N1) and B. Because of increasing resistance to oseltamivir, this drug has been used with M2 ion channel inhibitors as 2-drug therapy for influenza A. Little data are not available on the safety of these 2 drug classes when used for treatment of influenza in pregnant women. This retrospective cohort study compared the maternal and neonatal outcomes of pregnant women treated antepartum for influenza with M2 ion channel inhibitors (amantadine, rimantadine), oseltamivir, or a control group. The study was conducted during 5 influenza seasons at a hospital in Texas. The comparative data showed that antepartum treatment with M2 ion channel inhibitors (n = 104), oseltamivir (n = 135), and a control group (n = 82,097) were not associated with increased rates of the following outcomes: gestational diabetes (P = 0.388), preterm birth (P = 0.190), premature rupture of the membranes (P = 0.154), or preeclampsia (P = 0.209). No differences were found among the 3 groups regarding the duration of hospital stay for the mother or the infant, the incidence of fever in labor, stillbirth, or major or minor malformations. Moreover, there were no significant differences among singleton live-born neonates without major malformations in fetal weight (P = 0.186), number of neonates who required intubation (P = 0.552) or intensive care nursery admission (P = 0.418), or the incidence of hyperbilirubinemia (P = 0.282). There were no neonatal deaths among live-born singletons and none had grade 3 or 4 intraventricular hemorrhages or seizures. Two preterm neonates exposed to antivirals in the second trimester developed necrotizing enterocolitis. One was exposed to amantadine and the other to oseltamivir. These findings show that antepartum-antiviral exposure does not increase the risk of adverse maternal or neonatal outcomes.