Women, Wellness, & Wisdom

Prevention of the Flu in Pregnancy

Prevention of the Flu in Pregnancy

By Vandna Jerath, MD

Dr. Jerath will be interviewed live on Denver Channel 7News regarding this topic on October 5, 2010 at 6:30am.

Although the hype may have calmed down about the
pandemic 2009 H1N1 flu , both 2009 H1N1 flu and the seasonal flu remain important concerns in pregnancy.  The U.S. Public Health Emergency determination for 2009 H1N1 influenza expired on June 23, 2010 and the World Health Organization (WHO ) formally declared an end to the 2009 H1N1 influenza global pandemic on August 10, 2010. The Centers for Disease Control and Prevention (CDC ) feel that the 2009 H1N1 virus will continue to circulate as part of seasonal influenza and have an impact on pregnant women. 

Influenza, known as the flu is a respiratory illness with seasonal epidemics typically from October through April with a peak in the U.S. in January.   The flu accounts for numerous complications, hospitalizations, and deaths each year.  In the U.S., studies have shown that flu related hospitalizations may exceed 200,000 per year and that over the past 30 years deaths may range from 3,000-49,000 per year. People who have a greater chance of serious flu complications include children younger than 2 years old, adults 65 years and older, pregnant and postpartum women, people with chronic medical conditions or weak immune systems, and people younger than 19 years of age on long-term aspirin.

In 2009, only 1% of the population was pregnant, but pregnant women accounted for 5-6% of H1N1 flu-related deaths.  Pregnant women have physiologic changes in their bodies with include an altered immune system as well as changes to their circulatory (heart) and respiratory (lungs) systems which results in a decrease in functional residual capacity, an increase in cardiac output, and an increase in oxygen demand.  These changes make them more susceptible to severe illness, complications, hospitalization, and even death from the flu.  Some of these complications include dehydration, pneumonia, acute respiratory distress syndrome (ARDS ) requiring mechanical ventilation, miscarriage , preterm labor, preterm delivery and birth.  An estimated 25 of 10,000 pregnant women in the third trimester will require hospitalization due to flu related problems.  During pregnancy, women have a four to fivefold increased rate of serious illness and hospitalization with influenza.

The influenza vaccination is the best way to prevent the flu.  Studies have shown the flu shot can reduce your chances of catching the flu by 70-90% in healthy individuals and reduce the risk of hospitalization or death by 50%-80% in high-risk individuals.  Studies also show that currently only 15-25%  of pregnant women receive the flu shot annually.  Flu vaccination of pregnant women can reduce febrile flu illness by more than 30% in mothers and their young infants as well as reduce influenza infections in 0-6 month old infants by 63%.  Use of the influenza vaccine reduces costs overall and can result in a savings of $50 per immunized pregnant woman.

On September 15, 2010, The CDC along with the American College of Obstetricians and Gynecologists (ACOG) and nine other medical organizations (AAFP, AAP, ACNM, AMA, ANA, AOA, APhA, AWHONN, and March of Dimes) released a statement  recommending that ALL pregnant and postpartum (including after pregnancy loss) women receive the seasonal influenza vaccine for 2010-2011.  The key points from this statement are as follows:

  • Pregnant women are more prone to severe illness from influenza.
  • Vaccination during pregnancy protects both the mother and her infant (up to 6 months of age).
  • Influenza vaccine is safe as it has been given to millions of pregnant women and has not demonstrated harm to women or their infants.
  • Influenza vaccine can be given to pregnant women in any trimester.
  • Pregnant women should receive the inactivated vaccine (killed virus) or flu shot, but NOT the nasal spray vaccine (live attenuated virus) which is contraindicated.
  • Postpartum women – especially within two weeks after pregnancy or pregnancy loss – should also receive the flu vaccine and may receive either the shot or nasal spray.
  • Women who are breastfeeding are encouraged to receive either type of vaccine and can pass antibodies via the breast milk to their infants that may provide passive immunity.  This is one of the best ways to protect infants under 6 months of age, who are too young to be vaccinated.

On September 21, 2010, ACOG released a statement  encouraging healthcare providers to educate and offer influenza vaccination to all their patients and especially pregnant patients.  They stated that ALL pregnant women should get the flu vaccine in any trimester and that flu prevention is an essential part of prenatal care.  The CDC also supports that getting the flu shot is the first and most important step in protecting pregnant women and their infants against the flu.

The October 2010 Committee Opinion – Influenza Vaccination During Pregnancy by ACOG, addresses  the use of thimerosal , a mercury containing preservative in flu shots,  and indicates that it does not cause any adverse effects except for occasional local skin reactions.  Numerous studies do not show an association with autism or other problems in infants to immunized mothers.  However, for those mothers that remain concerned, a thimerosal –free flu shot is also available.

Symptoms of the flu include fever, cough, sore throat, runny nose, congestion, muscle and body aches, headaches, fatigue, and in some cases vomiting and diarrhea.  Sick individuals may be able to infect others and shed the virus starting 1 day before symptoms and up to 5-7 days after becoming ill.  In pregnant women, the flu can rapidly progress and worsen.  Treatment is typically, supportive care with rest and fluids.  Pregnant women are encouraged to treat any fevers with Tylenol, especially because in the first trimester hyperthermia can lead to birth defects and in labor maternal fever can lead to neonatal seizures, encephalopathy or cerebral palsy.  Treatment with antivirals may be recommended and ideally work best if started within the first 48 hours of symptoms, but may still provide some benefit if started later.  The two FDA approved antivirals are Tamiflu and Relenza.  Tamiflu is preferred for pregnant women as it is absorbed systemically. Pregnant women who think they may have the flu should also see their doctor immediately if they experience:

  • Difficulty breathing or shortness of breath
  • Pain or pressure in the chest or abdomen
  • Sudden dizziness
  • Confusion
  • Severe or persistent vomiting or diarrhea
  • High fever not responding to Tylenol or acetaminophen
  • Decreased fetal movement
  • Regular uterine contractions with concern for preterm labor
  • Vaginal bleeding or possible leakage of amniotic fluid


In summary, the CDC outlines “Take 3” key actions to fight the flu:


  1. Take the time to get a flu vaccine. –

    • Yearly flu vaccine recommended for EVERYONE 6 months of age or older.
    • Particularly important for people at high risk for flu complications including children under 2 years of age, pregnant and postpartum women, people with chronic illness or immuno-compromised, and those over 65 years and older.
    • 2010-2011 is a trivalent seasonal vaccine which covers influenza A 2009 H1N1, influenza A H3N2, and influenza B.
    • Health care workers, childcare providers, nursing home residents, and caretakers of the high risk or chronically ill should also get vaccinated.

  2. Take everyday preventive actions to stop the spread of germs.

    • Cover your nose and mouth when sneezing or coughing.
    • Wash your hands.
    • Avoid touching eyes, nose, or mouth.
    • Avoid close contact with sick people.
    • Stay home for at least 24 hours after your fever is gone if you are sick with the flu.

  3. Take flu antiviral drugs if your doctor prescribes them.

    • These drugs can shorten the duration of your flu symptoms and help prevent serious flu complications.
    • Ideally, antivirals should be started within the first 48 hours of symptoms, especially for those at increased risk for flu complications such as pregnant women, young children, the elderly, or chronically ill individuals.


The flu vaccine should not be given to children younger than 6 months of age, individuals with a severe egg allergy, anyone with a prior severe reaction or a history of Guillian-Barre Syndrome (GBS) after vaccination, or someone with a current fever should wait for immunization until the fever resolves.


The flu vaccination is recommended for everyone over 6 months of age and an important measure for public health prevention.   As pregnant women are particularly vulnerable to the flu and more susceptible to increased morbidity and mortality, it is essential for all pregnant women, women planning to be pregnant during flu season, postpartum women, and women breastfeeding to get the flu vaccination.   Please get your flu shot for your overall health and wellness and to help prevent this epidemic.   


One thought on “Prevention of the Flu in Pregnancy

  1. Pingback: 15 Facts About the Flu & Flu Shot in Pregnancy | Dr. Jerath

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