Getting a Flu Shot When You’re Pregnant

It is recommended that pregnant people get a flu shot during pregnancy to help protect against severe cases of influenza (the flu).

Normal changes in the immune system during pregnancy can increase a pregnant person’s risk of serious complications from the flu that could result in hospitalization and, in some cases, even death.

Research has shown that it’s safe to get the flu shot during any trimester of pregnancy to help protect both the pregnant person and their baby from influenza-related health problems during and after pregnancy.

Purpose

The annual flu shot (vaccine) triggers the immune system to make protective antibodies against the contagious respiratory flu virus. This helps reduce your chances of getting sick.

During pregnancy, the body goes through changes to the immune system, heart, and lungs that make pregnant people more susceptible to severe symptoms and complications from viruses like the flu. In some cases, getting sick may require hospitalization.

Even if you’re considered a healthy pregnant person, your body may still have a difficult time fighting off a flu infection. You could develop breathing problems, high fever, and other serious complications.

Getting a flu shot reduces the chances that you’ll get sick from the flu virus. If you do catch the virus, your reaction will likely be milder if you’ve been vaccinated. In fact, getting a flu shot while pregnant has been shown to reduce a pregnant person’s risk of being hospitalized with the flu by an average of 40%.

Importance

The flu is more likely to cause severe illness in pregnant people than in people of child-bearing age who are not pregnant, according to the Centers for Disease Control and Prevention (CDC).

The CDC classifies pregnant people and people who have given birth in the past two weeks as being at high risk for developing flu complications.

Since they are at increased risk, flu vaccination is especially important and highly recommended for most pregnant people. However, there are a few rare exceptions.

In addition to protecting pregnant people against the flu and its complications, getting a flu shot during pregnancy can also be helpful in other ways.

• Protect the baby against the flu. Babies are at an increased risk for getting severe cases of the flu, but cannot get the flu vaccine until they are 6 months old. If a baby’s caregivers are vaccinated against the flu, the baby is less likely to be exposed to the virus. Additionally, when a pregnant person gets a flu shot, they pass antibodies to their baby to help protect them from the virus until the baby is able to get their flu shot.
• Reduce the risk of certain pregnancy complications. Pregnant people who get the flu are more likely to experience complications like preterm labor and birth, miscarriage, and stillbirth than people who don’t get sick from the flu while they are pregnant.
• Prevent potential health problems for the baby. Having a fever (a common symptom of the flu) during pregnancy has been associated with neural tube defects (a category of serious birth defects). Getting the flu while pregnant may also contribute to higher chances of having a baby born with low birth weight or a baby small for gestational age.

Side Effects

The CDC tracks side effects and reactions to the flu shot and has found that in all people, severe side effects and reactions are rare. Side effects experienced after getting a flu shot while pregnant are usually mild and should go away after a day or two.

The most common side effects are similar to cold symptoms and may include:

• Headache
• Fever
• Nausea
• Muscle aches
• Fatigue
• Sore arm at the injection site

If you experience a common side effect after the flu shot that does not go away after a few days, make sure to call your doctor.

Risks

Getting a flu shot during pregnancy is considered to be safe, effective, and low risk. Numerous studies have proven the safety of the annual influenza vaccine for pregnant people and their unborn babies.

In fact, research that included more than two million pregnant people around the world found that the vaccine reduced the risk of being hospitalized from the flu by an average of 40%, regardless of the trimester in which a person received the flu shot.

Some common myths about the risks of getting a flu shot during pregnancy have been proven false by the CDC and numerous health agencies.

• There is no risk of getting the flu from a flu shot while pregnant. It’s an inactivated vaccine, meaning that it does not contain an infective or active virus that could get you sick.
• Flu vaccine ingredients are safe for pregnant people. Some multi-dose flu shots are made with an ingredient called thimerosal, which is a mercury-based preservative. Federal health agencies and major medical organizations agree that it’s safe and effective for pregnant people, with no evidence that it causes harm aside from minor redness and swelling at the injection site. If you’re still concerned, ask your doctor for a preservative-free flu shot.
• Getting a flu shot during pregnancy does not increase the risk of miscarriage. Despite reports from a few small studies with limitations, the CDC has reassured the public that there is no link between miscarriages and the flu shot. Miscarriage can happen in any pregnancy, regardless of vaccine use. Rest assured that medical experts are continuing to study and monitor flu shots in pregnant people to ensure it remains safe.

A Word From Verywell

Getting a flu shot during pregnancy is recommended for a reason: to protect you, your baby, and others who might be at risk of serious illness from the flu. The flu shot has been given to millions of pregnant people over many years and has a good safety record.

Flu vaccination during pregnancy is so important that if the flu shot is in short supply, the CDC recommends prioritizing flu shots for certain groups—including pregnant people and babies ages 6 months and older.

If you have any questions or concerns about getting a flu shot while you are pregnant, talk to your OB-GYN or primary care doctor.