Influenza in Pregnancy: Prevention and Treatment

I am Dr Sonja Rasmussen, acting director of the Office of Public Health Preparedness and Response at the Centers for Disease Control and Prevention (CDC). I am happy to speak with you today as part of the CDC Expert Video Commentary Series on Medscape.

Seasonal influenza activity is expected to pick up soon, and pregnant women are at increased risk for influenza-associated complications. Today I will highlight important information for your pregnant patients about the risks associated with influenza for pregnant women and their babies, and why pregnant women should get vaccinated against influenza. In addition, I will discuss treatment recommendations for pregnant women who become ill with influenza this season.

Dr Denise Jamieson and I recently authored a commentary, published in the New England Journal of Medicine,^[1] that discussed ways to protect pregnant women and their infants from influenza. We have learned that pregnant women are often unaware that they are at high risk of developing influenza-related complications. Changes in their immune system, heart, and lungs during pregnancy make pregnant women more prone to severe illness, hospitalization, and even death from influenza.

Influenza Vaccination in Pregnancy

Pregnant women are often unaware of the benefits of influenza vaccination for their babies. CDC recommends that everyone 6 months and older get vaccinated against influenza each year. An influenza vaccination is the best protection currently available against influenza. Receiving an influenza vaccine during pregnancy not only reduces a pregnant woman's risk for influenza infection, but also the risk for her infant to become ill with influenza during the first 6 months of life, when the baby is too young to receive the flu vaccine. Studies^[2] have shown that vaccinating the mother during pregnancy also may reduce the occurrence of such adverse pregnancy outcomes as small size for gestational age and preterm birth.

Inactivated influenza vaccine—the flu shot—is safe for pregnant women and can be administered during any pregnancy trimester. Live attenuated influenza vaccine (LAIV, or the nasal spray) is not recommended for use during pregnancy.

As a healthcare provider, your recommendation and offer of flu vaccine are critical motivators for pregnant women to be vaccinated. Healthcare providers should inform pregnant women of their increased risk of developing influenza-related complications and encourage them to get vaccinated. Pregnant women should also be informed that flu vaccine during pregnancy can protect the baby from getting sick with influenza during the first 6 months of life.

The flu shot is recommended during pregnancy by both the Advisory Committee on Immunization Practices and the American College of Obstetricians and Gynecologists. Over the years, millions of pregnant women have received a flu shot, and it has not been shown to harm pregnant women or their babies. As a healthcare provider, you can help protect your patients and set a good example by getting vaccinated, too.

Treatment of Influenza in Pregnancy

If a pregnant woman becomes sick and is suspected of having influenza, it's important that she receive prompt antiviral treatment. Pregnant women with confirmed or suspected influenza should be treated with oseltamivir as soon as possible, regardless of pregnancy trimester. Pregnant women are recommended to receive the same antiviral dosing as nonpregnant women.

Your decision to treat should be based on your clinical evaluation rather than on diagnostic testing because of the limited sensitivity of rapid influenza diagnostic tests and the time required to complete more definitive testing. Ideally, antiviral treatment should begin within 48 hours of the onset of symptoms. For that reason, pregnant women with symptoms of influenza should be encouraged to seek care early in their illness. However, treatment of pregnant women appears to be of clinical benefit, even when that treatment is started more than 48 hours after symptom onset. Available data^[3] indicate that oseltamivir does not harm the fetus when given to a pregnant woman.

In closing, your recommendation and offer of flu vaccine to your patients can make a difference. For more information on flu and pregnancy, please check out the resources on this page.

Web Resources

Pregnant Women and Influenza (Flu)

Flu Vaccination: A Growing Trend Among Pregnant Women

Preventing Flu During Pregnancy

Influenza (Flu) Print Materials: Pregnant Women

Study Finds Flu Vaccine Reduces Risk of Flu Illness in Pregnant Women by Half

Sonja Rasmussen, MD, is the Acting Director of the Office of Public Health Preparedness and Response (PHPR) at the Centers for Disease Control and Prevention (CDC). Dr Rasmussen joined the CDC in 1998 and has since provided significant scientific expertise and leadership. She led CDC's pandemic planning efforts for pregnant women before the 2009 H1N1 outbreak, including convening planning meetings of experts and public health partners focused on weighing the risks and benefits of treating pregnant women with antiviral medications and using pandemic influenza vaccine during pregnancy. Outcomes from this meeting guided CDC's recommendations during the 2009 H1N1 pandemic related to pregnant women.

Dr Rasmussen received her BS in biology and mathematics with magna cum laude honors from the University of Minnesota-Duluth, her MS degree in medical genetics from the University of Wisconsin, and her MD degree with honors from University of Florida. She completed her pediatrics residency at Massachusetts General Hospital and her fellowship in clinical genetics at Johns Hopkins Hospital and the University of Florida. She is board certified in pediatrics, clinical genetics, and genetic counseling and has authored or coauthored over 180 peer-reviewed papers.