Hopkins PodBlog

H1N1 Infection in Pregnancy


H1N1 infection in pregnant women seems to be associated with a much higher rate of mortality than any other group reported so far. That's according to a Lancet Infectious Disease study: H1N1 2009 influenza virus infection during pregnancy in the USA. In this relatively small number of women (34), 11 were admitted to the hospital and 6 of them died. So mortality was approximately 50% among those hospitalized with the flu.

That is, of course, a very high rate of mortality. These women died of primary pneumonia related to the influenza infection. They developed pneumonia and its consequent breathing problems several days after being infected with H1N1. In contrast, many people who have had the flu may develop secondary pneumonia, often with a bacterium such as Streptococcus pneumoniae. This happens because their immune systems are weakened from the flu and the bacterium gains the upper hand, causing pneumonia. One public health message from this more typical scenario is if you have had the flu, seem to be getting better and then suddenly develop a fever and perhaps breathing problems, seek immediate medical attention.

The advice for pregnant women is even more urgent: if you have what appears to be the flu, with fever, muscle aches and pains, perhaps respiratory symptoms, go to an emergency department. H1N1 remains sensitive to oseltamivir and zanamivir, two antiviral drugs, but drug therapy must be initiated early in the course of infection to be effective. Women who died in this study did not receive the medications in a timely fashion, most likely because of health care providers' reluctance to use any medications during pregnancy. Indeed, no one knows the effect of antiviral drugs on the developing fetus, but we do know that untreated women will die at a high rate. Keeping mom alive, therefore, seems to win out in the risk/benefit analysis.

Another public health message is if you're pregnant or contemplating pregnancy, get a flu shot. Other topics in our podcast this week include: Induction of labour versus expectant monitoring for gestational hypertension or mild pre-eclampsia after 36 weeks' gestation (HYPITAT): a multicentre, open-label randomised controlled trial, Addition of infliximab compared with addition of sulfasalazine and hydroxychloroquine to methotrexate in patients with early rheumatoid arthritis (Swefot trial): 1-year results of a randomised trial, both from the Lancet, and Screening for Intimate Partner Violence in Health Care Settings from JAMA. Until next week, y'all live well.