H1N1 and Pregnancy

During my travels to Latin American countries contending with the disease in their winter season, I learned that pregnancy has been recognized as a risk factor for serious disease outcome with influenza strains in general. Pregnant women who contract the current version of pandemic H1N1 influenza risk being in an ICU and dying of the infection. H1N1 targets young adults - not the very young children and elderly as past circulating strains of seasonal influenza do. As a result, more young woman are at risk.

Two risk factors- morbid obesity and pregnancy - both conditions overrepresented among dying patients with H1N1, share a degree of insulin resistance. This is a metabolic condition which can predispose to infection. It is also possible that pregnancy and obesity have low lung volumes in common that may be contributing to severity. While this is based on speculation, it is my hope that scientific studies will examine why H1N1 causes such severe disease in pregnancy.

The key public health implications are that pregnant women should be a high priority to receive a future safe H1N1 vaccine. In the meantime they should avoid contact with any patients who might have the pandemic strain.

During my time in Latin America, I uncovered the following supporting evidence:

• In Brazil, I learned that pregnancy was a risk factor for needing intensive care treatment after infection with H1N1.

• In Columbia, one of seven reported deaths in adults with H1N1 was in a pregnant woman.

• In Argentina, of 85 deaths after H1N1 in the region of Buenos Aires, one fourth were in pregnant women. Obesity, which was recognized as a likely risk factor for dying in Mexico and more recently in the United States, was a close second to pregnancy among those dying of H1N1 in the same region.