Sunday, January 8, 2012

Influenza and pregnancy

The first thing that needs to be said is, it’s not too late to get vaccinated against flu! In the U.S., flu season typically peaks around February, sometimes as late as April or May.

The American College of Obstetricians and Gynecologists (ACOG), the American Academy of Family Physicians, the American Academy of Pediatrics and the CDC’s Advisory Committee on Immunization Practices (ACIP) recommend that all pregnant and postpartum women receive a flu vaccine. So, if you’re already pregnant, it’s still not too late to get a flu shot.

You can use the Flu Vaccine Finder to find a provider near you.

Some of the changes that occur during pregnancy place women at higher risk of complications from influenza, especially during the second and third trimesters. A pregnant woman’s body needs more oxygen but she is less able to take a deep breath. There are changes in a woman’s immune system that protect the baby but decrease her ability to fight infection. A woman’s heart also works harder during pregnancy. Pregnant women are four to five times more likely than the general population to become seriously ill and require hospitalization due to influenza.

What is influenza?

In talking to people about flu, it seems that there is some confusion about what flu is. I’ll start by talking about what flu is not:

Influenza is not “stomach flu.” Even though some people may be nauseated and throw up when they have the flu, influenza is a respiratory disease, not a gastrointestinal disease. What people call “stomach flu” (nausea, vomiting, and diarrhea) is usually viral gastroenteritis.

Influenza is not a “bad cold.” There are lots of viruses that cause the common cold. Both influenza and the common cold can cause coughing and runny nose, but the symptoms of flu are usually much more severe. Like the cold, influenza is a respiratory disease, but the systemic symptoms of flu (fever, chills, muscle aches, and headache) are worse than the respiratory symptoms.

To add to the confusion, there are many “influenza-like illnesses” (ILI) that are not influenza. Parainfluenza viruses, respiratory syncytial virus, and adenoviruses can cause illness that is indistinguishable from influenza.

People shed influenza viruses and can infect others for up to a day before the onset of symptoms and continue to shed influenza viruses for up to ten days after symptoms start. Children and people with immune deficiencies can shed influenza viruses much longer than that. A person infected with influenza can transmit flu to other people before knowing that she or he has the flu and can continue to infect other after beginning to feel better.

So, influenza is a viral respiratory disease that causes fever, chills, muscle aches (myalgia), headache, and cough.

Influenza also knocks people off of their feet. Flu usually keeps people in bed and away from work or school for three days and can take a week or more for otherwise healthy people to recover.

Influenza also kills people. A graph of influenza deaths by age shows a U-shaped pattern, with relatively few deaths in the middle, and higher number of deaths in young children and older adults. People with chronic medical conditions are also more likely than healthy adults to develop complications from influenza or die. The most common complication associated with influenza is pneumonia.

Next I’ll talk about influenza vaccines.


American College of Obstetricians and Gynecologists. (2010). Influenza vaccination during pregnancy. Committee Opinion No. 468. Obstetrics & Gynecology, 116(4), 1006-1007.

Centers for Disease Control and Prevention. (2010). Prevention and control of influenza with vaccines: recommendations of the Advisory Committee on Immunization Practices. Morbidity and Mortality Weekly Report, 59(8).

Lee, F. E. & Treanor, J. (2010). Viral infections. In Murray and Nadel’s textbook of respiratory medicine. (5th Ed. pp.). [Electronic version].

MacDonald, N. E., Riley, L. E., & Steinhff, M. C. (2009). Influenza immunization in pregnancy. Obstetrics & Gynecology, 114(2, Part 1), 365-368. doi:10.1097/AOG.0b013e3181af6ce8.

Tamma, P. D., Ault, K. A., del Rio, C., Steinhoff, M. C., Halsey, N. A. & Omer, S. B. (2009). Safety of influenza vaccination during pregnancy. American Journal of Obstetrics and Gynecology, 201(6), 547-552.

Treanor, J. J. (2009). Influenza viruses, including avian influenza and swine flu. In Mandell, Douglas, and Bennett’s principles and practice of infectious diseases. (7th Ed.). [Electronic version].

No comments:

Post a Comment