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A doctor administering a flu shot to a pregnant woman

Your flu shot pregnancy guidelines

Mary Van DorenVerified

Senior Editor

10 positive reviews
Will a shot affect your baby?

Because the contents of a flu shot are inactive, getting a flu shot is harmless to your unborn baby and is strongly recommended.

Pregnancy can pull expecting mothers through an intense rollercoaster of hope and fear. Women often find themselves asking tough questions without concrete answers: Will my child have the best possible health as they enter the world? What sort of world will they enter? What can I do to prepare myself for parenthood?

One question women shouldn’t have to spend too much time pondering is whether it’s safe to get the flu shot during pregnancy.

The answer is definitive. The federal Centers for Disease Control (CDC), the American College of Obstetricians and Gynecologists (ACOG), the American College of Nurse-Midwives, and many other organizations all strongly recommend that pregnant women get a flu shot.

Seeking to understand seasonal and geographic trends surrounding flu shots, JustAnswer analysts compared pregnancy-related flu shot traffic on the site in 2016 to 2017 and found an overall 178% increase in 2017, suggesting this issue is top of mind for a growing number of Americans.

Flu shot pregnancy data suggestion an increase in question volume for 2017
As flu shots become more widespread and the debate about their ostensible risks rages, men are beginning to show a more active role.

Interestingly, more men are also taking part in the conversation. In 2016, men were responsible for only 1 in 12 visits about the topic. In 2017, that number jumped to 1 in 7. As attitudes about gender roles in the workplace and family continue to evolve, men seem to be taking a more active role in the prenatal health of their partner.

State-specific data also yielded a heat map of where people are asking the most questions. Illinois, Michigan, Georgia, North Carolina, and Washington rounded out the top-five states most interested in flu shots during pregnancy. The District of Columbia showed proportionally deep interest relative to its population.

Which states asked the most questions about flu shots during pregnancy in 2017?
States like Illinois, Michigan, Georgia, North Carolina, and Washington asked a preponderance of questions about pregnancy and vaccinations relative to their populations.

How safe is the flu shot during pregnancy?

The CDC notes that studies show flu vaccines are safe for women in any stage of pregnancy. As JustAnswer Expert Valarie says, "As long as you got the injectable vaccine, which is made of inactivated virus, there is nothing to worry about."

Flu shots protect both mother and baby, because mothers pass on the flu-fighting antibodies to their baby during the pregnancy, a protection that is believed to last as long as the first four months of life.

A t-cell responsible for immune response after infections like the flu
The t-cell, pictured here, is a kind of white blood cell that fights off infections like the flu when the body needs an immune response.

No matter how healthy and strong you are, pregnancy makes it harder for your body to fight infections. And flu can cause major problems, such as pneumonia and even death, in women who are in any stage of a pregnancy. Women who get very sick from the flu may be at increased risk for pregnancy complications such as miscarriage or premature delivery. You also have a higher risk of flu-related complications during the postpartum period.

The flu shot has been given to pregnant women in the U.S. since the 1960s. Studies of thousands of women who have received the flu shot just before or during pregnancy have found no increased risk for birth defects.

At the same time, symptoms of the flu, such as a high fever, could affect the developing baby. Also, infants who get the flu are at increased risk for severe disease from the flu. Since infants cannot receive the flu shot until they are six months old, vaccinating the mother (and other caregivers) reduces the chance that the baby may encounter the flu virus.

A nurse examines a newborn baby whose mother got a flu shot while pregnant
Newborn babies usually have to wait 6 months before getting a flu shot. Because pregnant women can transfer immunity to their unborn babies, doctors recommend expecting mothers get immunized.

When should I get the vaccine?

Because the flu includes thousands of strains and constantly evolves, there’s a new vaccine every year, created to fight the strains that scientists believe will be most dominant that year. The new vaccines are available starting in September. Protection begins about two weeks after you get the flu shot and lasts at least six to eight months.

Pregnancy doesn’t affect this guideline. The shot can be given at any time during pregnancy, so there is no recommended waiting period after getting a flu shot for becoming pregnant.

In fact, even if your due date is coming up fast, you should still get the shot in order to protect not only yourself, but your baby once he or she is born. You can even safely get the vaccine if you’re breastfeeding.

While you should consult with your doctor or caregiver before getting any medical care, there is no recommendation or requirement for pregnant women to get a doctor’s formal approval for the shot.

A doctor talking with a pregnant woman about her flu shot options
Although there's no formal need to get a doctor's approval for a flu shot, your doctor will know your exact situation and be in the best position to suggest a course of action.

What type of shot should a pregnant woman get?

As mentioned above, the vaccine is different every year. For the 2017-2018 season, vaccines include:

  • Trivalent vaccine: protects against two influenza A strains – H1N1 (swine; different from the 2016-17 vaccine) and H3N2 (swine variant; (same as in last year’s shot) – and one influenza B strain (same as in last year’s shot)
  • Quadrivalent vaccine: protect against the same strains as the trivalent vaccine, as well as an extra influenza B strain

The federal Centers for Disease Control (CDC) lists the contents of the current year's vaccine here.

These vaccines are delivered via needle. There are also several other forms of these vaccines:

  • A nasal spray, which is approved for healthy people ages 2 to 49
  • A small-needle version (intradermal flu vaccine) for people ages 18 to 64
  • An egg-free version that's grown in animal cells rather than hen's eggs and is approved for people ages 4 and older, who have egg allergies

The CDC recommends that pregnant women get the vaccine via injection.

One of the many misconceptions about the flu vaccine is that it can actually give you the flu. However, this is just not possible. The CDC explains that flu vaccines given with a needle are currently made in two ways: The injection vaccine is made either with flu vaccine viruses that have been ‘inactivated’ and are therefore not infectious; or with no flu vaccine viruses at all.

A bundle of FluMist vaccines, which deliver the vaccine through a nasal spray
The flu shot nasal spray is both riskier for pregnant women and less effective than flu injections.

However, the nasal spray contains live, weakened flu viruses, and is not recommended for pregnant women for that reason. And in any case, just like last year, the CDC is not recommending the nasal spray for anyone, based on lack of effectiveness.

 Also, according to JustAnswer Expert Nurse Milli, pregnant women who are allergic to eggs or have had a reaction to the flu vaccine before should inform their doctor before getting the shot.

Can I get the flu even if I get the vaccine?

No vaccine is 100% effective, and there are several reasons why you might get the flu, or think you have it, even though you’ve had the shot. The vaccine does vary in how well it works, and some people who get vaccinated may still get sick.

A pregnant woman lies down in bed with a cold
Although it's rare, it's possible to come down with the flu immediately after getting the flu shot. It takes the vaccine up to two weeks to immunize the body.

However, because the common cold has symptoms similar to the flu and is rampant during flu season, many people who think they have the flu are suffering from a cold or other respiratory illness. And, of course, there is no vaccine or medication that prevents colds.  Also, it takes two weeks after getting the shot for your body to become immune, so if you were exposed to the flu just before getting vaccinated or during the two weeks after, you could come down with flu after having the shot.

Also, because the flu's strains are constantly evolving, you could encounter a strain that the vaccine wasn’t designed to protect.

If you do get the flu while pregnant, or in the first two weeks post-partum, contact your health care provider immediately. Flu symptoms may include:

  • Fever or feeling feverish
  • Chills
  • Body aches
  • Headache
  • Fatigue
  • Cough or sore throat
  • Runny or stuffy nose

ACOG recommends that you take an antiviral medication, available by prescription, as soon as possible. It is most effective when taken within 48 hours of the onset of flu symptoms, but there still is some benefit to taking it up to 4-5 days after symptoms start. An antiviral drug does not cure the flu, but it can shorten how long it lasts and how severe it is.

Finally, some people express concerns about thimerosal, a preservative used in some vaccines to keep out harmful bacteria. It is found in small amounts in the large vials of vaccine used to hold several doses of vaccine. Single-dose vaccine vials do not contain thimerosal. Thimerosal has been well studied and there has been no evidence of any harmful effects. Pregnant women can safely receive vaccines containing thimerosal. If you still wish to avoid thimerosal, talk to your health care provider about this option.

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