Insights on Influenza Blog
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Pregnant & Postpartum Women

The number one way to protect pregnant women and babies younger than 6 months old from flu is for women to receive an inactivated flu vaccine (which means a flu shot, not the nasal flu mist) during any trimester of pregnancy.

Impact of Flu On Pregnant and Postpartum Women

Changes in the immune system, heart, and lung functions during pregnancy make pregnant women (and women up to two weeks postpartum) more likely to experience complications from flu. This can increase a woman’s risk of premature labor and delivery, hospitalization or even death. Flu may also present a risk to the health of a pregnant woman’s developing baby. But flu vaccination during pregnancy helps protect pregnant mothers from possible flu-related complications, while also helping to protect their babies both before and after delivery. 

Impact of Flu On Babies

Since infants can’t receive a flu vaccine until they are six months of age, getting a flu vaccine in pregnancy is the best way to pass on protection to your newborn. Studies show that babies born to mothers who’ve received a flu vaccine during pregnancy are:

70% less likely

to suffer with flu

81% less likely

to be hospitalized for flu during the first few months after birth

Anakin's Flu Story

Anakin was born 10 weeks premature as a result of his mother contracting influenza while pregnant. He now suffers from chronic lung disease.

Read Anakin's Story

Safety of Flu Vaccine in Pregnant Women
The Centers for Disease Control and Prevention (CDC) and the U.S. Food & Drug Administration (FDA) continually monitor the safety of flu vaccines licensed for use in the United States. Multiple studies have examined numerous years of data from the Vaccine Safety Datalink (VSD) and Vaccine Adverse Event Reporting System (VAERS), both of which are vaccine monitoring systems. These studies, in addition to other studies conducted by CDC and other health organizations, support the safety of flu vaccination for pregnant women and their unborn babies, and show that millions of pregnant women over many years have safely received a flu vaccine.1
Not only do many large studies show that flu vaccination is safe for mother and baby,2,3 but a large number of studies also indicate that adverse outcomes for both mother4 and baby5 - such as complications, hospitalizations and deaths - are reduced when women receive a flu vaccine during pregnancy.  A comprehensive list of studies evaluating the safety of flu vaccines in pregnancy can be found here.

Common Questions About Flu Vaccination in Pregnancy:

Can getting the flu vaccine contribute to miscarriage?

No. Multiple studies have shown that women who have received flu shots during pregnancy have not had a higher rate of miscarriage. The Advisory Committee on Immunization Practices (ACIP), the CDC, and the American College of Obstetricians and Gynecologists (ACOG) recommend flu vaccination for pregnant women during any trimester of their pregnancy because flu poses a danger to pregnant women and infants.

If I get the flu vaccine while pregnant, will my baby be exposed to thimerosal (or mercury) in utero?

Only multi-dose preparations of flu vaccine contain thimerosal, which is a preservative used to prevent contamination from bacteria and fungi. Flu vaccines containing thimerosal are considered safe for pregnant women and young children. Thimerosal contains ethylmercury (not to be confused with the toxic form of mercury called methylmercury, which can be found in certain kinds of fish). Ethylmercury is readily eliminated by the body and does not build up to harmful levels. If you’re worried about thimerosal, ask your health care professional for a thimerosal-free flu shot. For more information about thimerosal in vaccines, visit the Children’s Hospital of Philadelphia’s Vaccine Education Center website.

If I get the flu vaccine while pregnant, will my baby be exposed to formaldehyde in utero?

Formaldehyde is commonly used in flu vaccines to inactivate the flu virus that has been harvested from eggs or animal cells during the vaccine manufacturing process. Residual amounts of formaldehyde may be present in a flu vaccine, but the amount is comparable to, or less than, the amount naturally found in our bodies for human metabolism and building proteins, and is considered safe – even for young infants. For more information on formaldehyde in vaccines, visit the Children’s Hospital of Philadelphia’s Vaccine Education Center website.

What about taking more holistic approaches to flu prevention and treatment such as hand washing, Vitamin D, Vitamin C, or breastmilk?

While good hygiene and a healthy diet are important for all adults and their children, they can’t prevent flu as well as a flu vaccine. According to the CDC, the best way to prevent the flu is through annual flu vaccination.


Breastfeeding and Flu Vaccines

Breastfeeding women should get a flu vaccine to protect themselves and their babies from flu. Getting vaccinated reduces a mother's risk of getting flu and passing the flu on to her baby. This is especially important for children younger than 6 months old since they are too young to receive an influenza vaccine themselves. Women who get the flu vaccine while breastfeeding also pass along protective antibodies to their infants through breast milk. According to the Centers for Disease Control and Prevention (CDC), flu vaccination is safe for breastfeeding mothers and their infants. 

Common Questions About Breastfeeding and the Flu:

Is it safe to get vaccinated for flu while breastfeeding?

According to the CDC, flu vaccination is safe for breastfeeding mothers, as well as their infants. Women who get the flu vaccine while breastfeeding pass along protective antibodies to their infants through breast milk and help protect women and their babies from potentially serious flu illness.

While it is safe for breastfeeding moms to receive a flu shot, flu vaccination during pregnancy is preferable because it not only protects newborns immediately following birth, but also helps protect pregnant mothers from possible flu-related complications such as hospitalization.

Does breastfeeding protect my baby from flu?

Breast milk is the perfect food for your baby and protective antibodies in breast milk can help a baby’s developing immune system fight off infection. Generally, babies who are breastfed get sick from infections like the flu less often and less severely than babies who are not breastfed. However, breastfeeding alone is not a substitute for flu vaccination. 

In addition to getting vaccinated and breastfeeding, you can help protect your baby from flu by washing your hands frequently and ensuring that everyone who has close contact with your baby - such as other family members and caretakers - receive their annual flu vaccine as well.

Should I stop breastfeeding if I have been around someone with flu?

No. The combination of maternal flu vaccination and mothers’ milk will help protect your baby against the flu. Antibodies generated from vaccination and those found in breast milk play an important role in protecting young babies from germs while their immune systems are still developing.

Do I need to stop breastfeeding my baby if I am sick?

If you are sick, speak with your health care provider about precautions to protect your baby. If you have the flu, you should stay home to avoid spreading flu, contact your health care provider, and drink lots of fluids.

Can I take medicine to treat or prevent flu while breastfeeding?

While most medicines used to treat the flu are safe, you should always talk to your health care provider about medications you are taking to ensure they are safe to take while breastfeeding.

Can I continue breastfeeding if my baby is sick with flu?

Yes. One of the best things you can do for your sick baby is keep breastfeeding. Sick babies need more fluids, and breast milk is better for your baby than any other liquid because it also helps boost your baby’s immune system. Talk to your health care provider about the best ways to feed your baby breast milk if sickness is making breastfeeding a challenge. 

However, keep in mind that flu can be very serious in young babies. If your baby gets sick, call your baby’s health care provider right away. Quick treatment can help prevent serious flu complications.

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Page last reviewed: May 2020. 

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