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Ashley Roman, MD, MPH

Clinical Assistant Professor Department of Obstetrics and Gynecology New York University Langone Medical Center New York, NY

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Pregnancy and the Flu Shot

Pregnancy and the Flu Shot

I'll be pregnant during flu season, and I'm worried about having the flu vaccine. Is it safe?

Ask the Expert


I'll be pregnant during flu season, and I'm worried about having the flu vaccine. Is it safe?


Yes. That's why the U.S. Centers for Disease Control and Prevention recommend that healthy pregnant women get vaccinated against the flu no matter what trimester they are in. In fact, the American College of Obstetricians and Gynecologists call getting the flu shot an essential part of prenatal care.

After all, pregnancy doesn't protect you against the flu, and it may even increase your risk of getting sick because of pregnancy-related changes in your immune system. Various studies also find that pregnant women may have a fourfold higher risk of death during a severe flu season and a much higher risk of hospitalization for flu-related complications. The risk is even higher if women have another health condition, such as asthma.

While we don't know for sure about the effect of the flu on your unborn baby, some studies suggest that it could lead to complications, including miscarriage, premature labor or, in some rare situations, birth defects.

The risk from the vaccine, however, is small. Very rarely, women may develop a low fever. The most common side effects are headache, fatigue and a reaction at the injection site—meaning your arm stays sore for a bit. None, however, are serious enough to outweigh the risks of the flu and the benefits of protecting yourself against it.

The few studies conducted on pregnant women receiving the flu vaccine find that their response to the vaccine is similar to that of women who are not pregnant. There is also good evidence that the vaccine can protect your baby during the first few months of life. That's very important because infants under six months should not receive the influenza virus.

One important point, though, is that you should only be vaccinated with the "inactivated virus" form of the vaccine, the type given in an injection. Stay away from the nasal spray vaccine, which uses an "attenuated" or modified version of a live flu vaccine. The nasal spray vaccine is not licensed for use in pregnant women but is OK to have after delivery and while you're breastfeeding.

Some women have questioned me about the use of a preservative used in flu vaccines called "thimerosal." They worry it could negatively affect their unborn baby. Thimerosal, an organic mercury compound, has been used since the 1930s in some vaccines, including the flu vaccine. Studies of more than 100,000 children followed from birth to more than seven years of age found no relationship between thimerosal vaccines and disorders like autism.

However, if you're still worried, ask your health care professional for a thimerosal-free flu vaccine.

Bottom line? Talk to your health care professional about a flu vaccine. It's one of the few things in this world where you can get two for the price of one: One shot to protect two people!

Looking for more information about seasonal flu or the flu vaccine? Click here.

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