Health Alerts > 7/29/09 Pregnant Women and H1N1

Date:  July 29, 2009

Topics:  H1N1

National Update:

Pregnant women infected with the new H1N1 swine flu have a much higher risk of severe illness and death, U.S. government researchers said on Wednesday, confirming a trend that has worried global health experts.  While pregnant woman have always had a higher risk of severe disease from influenza in general, the new H1N1 virus is taking an exceptionally heavy toll, the researchers said.

"We do see a fourfold increase in hospitalization rates among ill pregnant women compared to the general population," Dr. Denise Jamieson of the U.S. Centers for Disease Control and Prevention said in a telephone interview.

"We're also seeing a relatively large proportion of deaths among pregnant women. We report 13 percent in the paper, but that is a very unstable number based on a small number of deaths reported," said Jamieson, whose study appears in the journal Lancet.

The study was based on the deaths of six pregnant women out of 45 deaths related to H1N1 reported to the CDC between April 15 and June 16.  All of the women were healthy prior to infection, and all developed pneumonia and needed to be put on a ventilator.

Jamieson said 302 deaths have been officially reported to the CDC from the new H1N1 virus.

"Among those, we have relatively complete information on 266 deaths. And of those, 15 have been among pregnant women, which is about 6 percent," Jamieson said.

Given that at any point, about 1 percent of the U.S. population is pregnant, she said, pregnant women "are definitely over-represented in terms of the proportion of deaths."

And she said doctors need to provide a separate waiting area for pregnant women who suspect they are ill, to protect healthy pregnant women from infection.

Jamieson said pregnant women with influenza should be given antiviral drugs as soon as possible, within the first 48 hours to be most effective.

Despite recommendations from the Advisory Committee on Immunization Practices and the American College of Obstetricians and Gynecologists that all pregnant women get a seasonal flu shot, less than 14 percent do, according to the CDC.

Guidance:  Pregnant Women Exposed to H1N1 (http://www.cdc.gov/h1n1flu/guidance/obstetric.htm)

Post exposure antiviral chemoprophylaxis can be considered for pregnant women who are close contacts of persons with suspected or laboratory confirmed novel influenza A (H1N1) virus infection. If chemoprophylaxis medications are being taken, exposed pregnant women can be managed in the usual way in compliance with established infection control guidance. Women who have symptoms of influenza-like-illness (defined as fever (temperature of 100°F [37.8°C] or greater) and a cough and/or a sore throat in the absence of a KNOWN cause other than influenza) should be treated as if they had influenza.

Pregnant Women with Confirmed, Probable, or Suspected H1N1 Illness

Special considerations in obstetric settings when a pregnant woman has confirmed, probable or suspected novel H1N1 flu (adapted from recommendations for seasonal influenza: http://www.cdc.gov/flu/professionals/infectioncontrol/peri-post-settings.htm) include:

• Initiate appropriate antiviral treatment as soon as possible.
• Isolate the ill mother from healthy pregnant women as mentioned above.
• Place a surgical mask on the ill mother during labor and delivery, if tolerable, in order to decrease exposure of the newborn, healthcare personnel, and other labor and delivery patients to potentially infectious respiratory secretions.
• Place the ill mother in isolation after delivery (http://www.cdc.gov/h1n1flu/guidelines_infection_control.htm).  The mother who has influenza-like-illness (http://www.cdc.gov/h1n1flu/casedef.htm) at delivery should consider avoiding close contact with her infant until the following conditions have been met: she has received antiviral medications for 48 hours, her fever has fully resolved, and she can control coughs and secretions.  Meeting these conditions may reduce, but not eliminate, the risk of transmitting influenza to the baby.  Before these conditions are met, the newborn should be cared for in a separate room by another person who is well, and the mother should be encouraged and assisted to express her milk. Breast milk is not thought to be a potential source of influenza virus infections. As soon as all conditions are met, the mother should be encouraged to wear a facemask, change to a clean gown or clothing, adhere to strict hand hygiene and cough etiquette when in contact with her infant, and begin breastfeeding (or if not able to breastfeed, bottle feeding). She should continue these protective measures, both in the hospital setting and at home, for at least 7 days after the onset of influenza symptoms (http://www.cdc.gov/h1n1flu/guidance_homecare.htm#c).  If symptoms last more than 7 days, she should discuss the symptoms with her doctor.  Protective measures might need to be continued until she is symptom-free for 24 hours.  People who are once again well 7 days after getting sick are thought to be at low risk for transmitting the virus to others.

Newborns of Ill Mothers

Because the risk for transmission of novel H1N1 flu from mother to fetus is unknown, the newborn should be considered to be potentially infected if delivery occurs during the 2 days before through 7 days after illness onset in the mother.  Infection control procedures developed for novel H1N1 flu should be used for the newborn throughout the hospital stay (http://www.cdc.gov/h1n1flu/guidelines_infection_control.htm). The newborn should be closely monitored for signs and symptoms of influenza. If signs or symptoms develop, testing should be performed, infection control measures should be continued, and treatment with anti-influenza medications should be considered (http://www.cdc.gov/h1n1flu/childrentreatment.htm).  Oseltamivir is approved for prevention of influenza in patients 1 year of age and older; however, an emergency use authorization (EUA) has been issued for Oseltamivir for influenza treatment and prevention in patients less than 1 year of age (http://www.cdc.gov/h1n1flu/recommendations.htm#C).

Chemoprophylaxis of infants less than 3 months of age is not typically recommended, as there are very limited data available on the safety and effectiveness of chemoprophylaxis for infants less than 3 months. However, in situations that are judged critical, chemoprophylaxis with Oseltamivir can be considered.  

State:

You may have heard that the sister of the young man who was the first Indiana death from H1N1 has also died from H1N1. 

The Advisory Committee on Immunization Practices (ACIP) is meeting on Wednesday and will make vaccine priority group recommendations to the CDC.  I will keep you informed when the information becomes available.

Feel free to call with any question,

Deb McMahan, MD