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Pregnant Women Are at Elevated Risk for Complications from H1N1 Flu

Pregnant women were more than four times as likely to be hospitalized as people in the nonpregnant general population.

During seasonal and pandemic influenza outbreaks, pregnant women generally have greater morbidity and mortality than other adults. At the beginning of the recent outbreak of novel H1N1 influenza, the CDC collected individual reports on all confirmed and probable cases and additional information on cases in pregnant women.

Between April 15 and May 18, 2009, the CDC received reports of 31 confirmed and 3 probable cases of novel H1N1 influenza in pregnant women. Symptoms of H1N1 influenza among pregnant women were similar to those among other infected people, except that dyspnea was reported about twice as often. Eleven pregnant women (32%) with H1N1 influenza were hospitalized, compared with 4% of the nonpregnant general population; the overall rate of hospitalization for H1N1 influenza was significantly higher among pregnant women than among others (0.32 vs. 0.076 per 100,000 people).

Of 45 deaths from H1N1 influenza that occurred between April 15 and June 16, 6 (13%) occurred in pregnant women. None of these women had serious underlying health problems; all received diagnoses of H1N1 influenza promptly and received oseltamivir, but, perhaps because of uncertainty about risks and benefits in pregnancy, all started treatment 6 days after symptom onset. Five of these women were carrying viable fetuses and underwent cesarean delivery; no vertical influenza transmission was noted.

Comment: Although these numbers are small, the data strongly suggest that pregnant women are at elevated risk for complications from H1N1 influenza. The CDC recommends that all pregnant women receive the H1N1 influenza vaccine (once it becomes available) and that those with influenza symptoms receive antiviral treatment without delay.

— Bruce Soloway, MD

Published in Journal Watch General Medicine August 13, 2009

Citation(s):

Jamieson DJ et al. H1N1 2009 influenza virus infection during pregnancy in the USA. Lancet 2009 Aug 8; 374:451.

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• HINI Flu and pregnant women
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