Pregnancy is such a special time for the entire expecting family. It is a time of planning and preparing for the birth of a child. It is also important to begin considering the steps you can take to help keep yourself and your baby protected from vaccine-preventable diseases – now and throughout your child’s life.

Before Becoming Pregnant

If you are planning to become pregnant, there are things you can do before and between pregnancies to increase your chances of having a healthy baby such as taking folic acid every day; quitting smoking, alcohol and street drugs; and making sure you are up-to-date on all recommended vaccines. Learn more.

Vaccines During Pregnancy

Vaccines are a part of a healthy pregnancy. When you get vaccinated during pregnancy, you are not only protecting yourself against dangerous, potentially deadly diseases, you are also passing immunity *directly* to your baby, offering them some early disease protection.

When a pregnant woman gets vaccinated, her body creates protective antibodies (immunity against diseases) and passes some of these antibodies to her baby that will last until her little one is ready to start getting their own vaccines.

Your OB-GYN or midwife can tell you which vaccines are right for you throughout your pregnancy, but the Centers for Disease Control and Prevention (CDC), the American College of Obstetricians and Gynecologists (ACOG), the American College of Nurse-Midwives (ACNM), the American Academy of Family Physicians  (AAFP); and the Association of Women’s Health, Obstetric and Neonatal Nurses (AWHONN) all strongly recommend the influenza (flu) and Tdap (whooping cough) vaccines for pregnant women. Take a look at the “Immunization for Pregnant Women: A Call to Action” from AAFP, ACOG, ACNM and AWHONN.

Flu Vaccine – The flu can cause serious health problems for pregnant women and their babies. Learn how getting the flu vaccine during pregnancy is safe and keeps both you and your baby protected from flu and its serious complications.

Tdap Vaccine – Whooping cough (also known as pertussis) can cause serious illness in people of all ages, but it is particularly dangerous for young babies. This is why pregnant women are recommended to get a Tdap vaccine during the 3rd trimester of every pregnancy. Learn how getting the Tdap vaccine during pregnancy is safe and keeps you and your baby protected from whooping cough and its possibly serious complications, including hospitalization and death.

Preparing for Your New Baby

Pregnancy is also good time to start thinking about the vaccines your baby will need once they are born. Especially because your little one will need their first vaccine before leaving the hospital.

Visit the Babies & Children section to learn more about the importance of vaccinating your child according to recommended immunization schedule.

Questions about the safety of vaccinating during pregnancy?  See answers below in Commonly Asked Questions About Vaccines for Pregnant Women, and find more answers to your vaccination questions in the Questions About Vaccines section of the website.

Commonly Asked Questions About Vaccines for Pregnant Women

Even breastfed babies need to be protected with vaccines at the recommended ages. While breast milk provides important protection from some infections like colds, ear infections and diarrhea, breast milk will not protect him or her against all diseases.

Your baby needs the long-term protection  that can only come from making sure they get all their vaccinations according to the recommended immunization schedule, before they are exposed to dangerous infectious diseases.

Yes. The flu shot is safe, during any trimester, for both you and your unborn baby. The flu shot has been safely administered to millions of pregnant women over many years. You can not get the flu from the flu vaccine.

It is also safe for women to get the flu vaccine while breastfeeding. In fact, breastfeeding also helps to protect babies because breast milk passes your antibodies to your baby, and these antibodies help fight off flu infection.

Following is a list of studies that show that the flu vaccine is safe during pregnancy. Click on the studies below to read the research.

The CDC and FDA monitor flu vaccine safety during pregnancy during each flu season using the Vaccine Adverse Event Reporting System (VAERS): An early warning system that helps CDC and FDA monitor health concerns following vaccination. Anyone can report possible vaccine side effects to VAERS.

In addition, CDC conducts research studies in the Vaccine Safety Datalink (VSD): A collaboration between CDC and nine healthcare organizations that do ongoing monitoring and proactive searches of vaccine-related data.

View the vaccine safety studies on flu vaccination during pregnancy.

Yes. See the research that has been done to make sure the Tdap vaccine during pregnancy is safe and effective for women and their babies.

No. The way that flu vaccines are made they cannot cause the flu. Flu shots are made from either flu viruses that have been ‘inactivated’ (killed) OR from proteins of a flu virus (instead of the full virus) so they can create an immune response without causing a flu infection.

While some people may get mild side effects from the flu shot like a sore arm, a headache, muscle aches or a low fever, those side effects usually begin soon after the shot and only last 1 -2 days.

Learn more about the current flu season.

The most common side effects from flu shots are soreness, redness, tenderness or swelling where the shot was given.  Some people also report having a low fever, headache and muscle aches. If these reactions occur, they usually begin soon after getting the shot and last 1-2 days.

Besides side effects, there are several reasons why someone might get flu symptoms, even after they have been vaccinated against flu.

  • Some people can become ill from other respiratory viruses besides flu such as rhinoviruses, which are associated with the common cold, cause symptoms similar to flu, and also spread and cause illness during the flu season. The flu vaccine only protects you from the flu, not other illnesses.
  • It is possible to be exposed to influenza viruses, which cause the flu, shortly before getting vaccinated or during the two-week period after vaccination that it takes the body to develop immune protection. This may result in a person becoming ill with flu before protection from the vaccine takes effect.
  • Some people may experience flu like symptoms even after getting vaccinated because they were exposed to a flu virus that is very different from the viruses the vaccine is designed to protect against. The ability of a flu vaccine to protect a person depends largely on the “match” between the viruses selected to make the flu vaccine that season and those spreading and causing illness. There are many different flu viruses that spread and cause illness among people.
  • The flu vaccine can vary in how well it works season to season, and sometimes people who get vaccinated may still get sick. However, the flu vaccine still offers important benefits. It will:
    • Reduce the severity of your illness if you got vaccinated, but still get sick from flu.
    • Reduce the risk of children dying from flu.
    • Reduce the risk of flu-associated hospitalization for children and adults.
    • Help protect people around you, including those who are more vulnerable to serious flu illness due to age and/or certain chronic health conditions.
    • Help protect people with certain chronic conditions from serious health complications.
    • Help protect women during and after pregnancy.

Yes. Studies shown that getting the Tdap (whooping cough) vaccine while you are pregnant is very safe for you and your baby. Severe side effects are extremely rare. You cannot get whooping cough from the Tdap vaccine.

OB-GYNs and midwives who specialize in caring for pregnant women agree that the Tdap vaccine is very important to get during the third trimester of each pregnancy. Getting the vaccine during your pregnancy will not put you at increased risk for pregnancy complication, and will help your baby be born with some protection against whooping cough.

To read some of the research on Tdap vaccination of women during pregnancy, click on the links to the studies below. More research is available on the CDC website.

By getting vaccinated with the Tdap vaccine between the 27th and 36th week of pregnancy (during your 3rd trimester), your body makes protective antibodies (immunity against disease) to pass on to your baby so he or she is born with protection against whooping cough. These antibodies will help increase your baby’s immunity from whooping cough until he is able to begin his own series of whooping cough vaccinations (DTaP) at 2 months of age. Tdap vaccine also protects mothers during delivery and makes them less likely to pass whooping cough to their newborn.

A study published in Pediatrics in May 2017 looked to see how effective the Tdap vaccine was at preventing whooping cough in babies whose mothers got the vaccine while pregnant or in the hospital after giving birth. The study found that getting Tdap between the 27th through 36th weeks of pregnancy is 85% more effective at preventing whooping cough in babies younger than 2 months old.

Additionally, authors of the study, Sources of Infant Pertussis Infection in the United States, which was published in October 2015 in Pediatrics, stated that vaccinating pregnant women with Tdap should directly increase protection of infants, regardless of the source of infection.

Yes. Pregnant women can safely get the Tdap vaccine even if they recently got a tetanus-containing vaccine (Td or Tdap).

It does not matter when you got your last tetanus shot (Tdap or Td vaccine), you still need the Tdap vaccine during the 3rd trimester of each pregnancy to protect yourself and your newborn from whooping cough.

The protection (antibodies) that you pass on to your baby before birth is very important and will give him or her some early protection against flu and whooping cough. However, these antibodies will only give your baby short-term protection. Therefore, it is also very important for him to get vaccinated according to the recommended childhood immunization schedule so he can start building his own protection against these dangerous diseases.

You may have heard that vaccines contain all types of crazy ingredients that sound as though they don’t belong in a medical product. The truth is that a very small group of very vocal, but misinformed, individuals have made false accusations regarding the safety of vaccines and their ingredients. In most instances these allegations are just wrong. In other cases, the claims are from information taken out of context or are trying to purposely mislead people.

The main ingredients in vaccines are antigens, which are small amounts of the bacteria or virus against which the person is being vaccinated. Antigens are the parts of the vaccine that encourage your immune system to create antibodies to fight against future infections. To make sure that the vaccines cannot cause the disease you are trying to protect against, the antigens are altered or weakened. Learn more about how vaccines are made and how they work.

Like many of the foods we eat and beverages we drink, vaccines also contain a small amount of additional ingredients, and each has a specific, necessary function. These ingredients may be added to the vaccine to make it more effective, sterile and/or safe. These additional ingredients have been studied and are safe for humans in the amount used in vaccines.

In fact, the amount of these additional ingredients in vaccines is much less than children encounter in their environment, food and water. As the saying goes, “the dose makes the poison.” In other words, any chemical – even water or oxygen – can be toxic or even deadly in large enough quantities.

Sometimes a child may be sensitive to one of the components of a vaccine, and an allergic reaction may result. For this reason, you should discuss any allergies your child may have with your healthcare provider. Below are the ingredients that may be found in certain vaccines and their purpose.


When an individual vaccine dose is drawn from a multi-dose vaccine vial with a new needle, it is possible for bacteria or fungus to get into the vial, which could be very dangerous to the people getting the shots. To prevent this contamination, a preservative is added to the vaccine vial.

Since 1968, the United States Code of Federal Regulations has required the addition of a preservative to multi-dose vials of vaccines; and worldwide, preservatives are routinely added to multi-dose vials of vaccine. Tragic consequences have followed the use of multi-dose vials that did not contain a preservative (including deaths) and are the driving force for this requirement.

Having safe, multi-dose vials of vaccines available for us to use is very important, especially when a large number of people need to be vaccinated quickly, which could be the case during a flu, coronavirus or other disease pandemic.


Thimerosal is a preservative used in multi-dose vials of flu vaccines to prevent contamination with bacteria or fungus, which could be deadly.

Thimerosal is made from a type of mercury call ethylmercury. This kind of mercury is broken down by the body and clears out of the blood quickly.

Ethylmercury is very different than methylmercury.

Methylmercury is found naturally in the environment. It is also the kind of mercury that is found in fish like salmon and shellfish; and also in many everyday products, foods and drinks.

Methylmercury accumulates in the body and takes much longer to remove from the body. A buildup of methylmercury in the body is usually due to eating certain types of fish or other drinks or food, and high amounts can harm the nervous system. Over a lifetime, everyone is exposed to some methylmercury.

Even though there was no evidence that thimerosal in vaccines was dangerous, in 2001, it was removed from vaccines in the U.S. in an effort to reduce overall mercury exposure among infants. To keep vaccines safe from contamination without the use of thimerosal or other preservatives, they were either reformulated or put into single-dose vials. Now, the only vaccines in the U.S. that use thimerosal as a preservative are flu vaccines in multi-dose vials. (Thimerosal-free, single-dose vials of flu vaccine are also available in the U.S.) There is no evidence that the small amounts of thimerosal in flu vaccines cause any harm, except for minor reactions like redness and swelling at the injection site.

No credible scientific studies have found an association between thimerosal in vaccines and autism. The studies used different methods to find out if there was any connection between thimerosal and autism. Some examined rates of autism a state or a country, comparing autism rates before and after thimerosal was removed as a preservative from vaccines. It is important to note that in the U.S. and other countries, the number of children diagnosed with autism has not gone down since thimerosal was removed from childhood vaccinesTo read the studies yourself, visit our Vaccine Research section.

The Global Advisory Committee on Vaccine Safety, which provides independent, authoritative, scientific advice to the World Health Organization (WHO) on vaccine safety issues of global or regional concern, has also concluded that there is no evidence of toxicity in infants, children or adults exposed to thimerosal in vaccines.

You can learn more about vaccines and autism on the Autism Science Foundation website.

Watch Now: Is there mercury (thimerosal) in vaccines? Is that dangerous?


Formaldehyde is a colorless gas that is a byproduct of metabolism so it is already present in the human body. People also encounter formaldehyde every day in the environment. It is used in making building materials and many household products, and formaldehyde also gets into the air through car tailpipe emissions.

Formaldehyde is used is used to inactivate bacterial products for toxoid vaccines (DTaP and Tdap), and to kill unwanted viruses and bacteria that might contaminate the vaccine during the manufacturing process. Most formaldehyde is removed from the vaccine before it is packaged. In very small amounts, formaldehyde is not dangerous. In fact, there is more formaldehyde in a pear than in any one vaccine.

Learn more about formaldehyde in vaccines from Vaccine Education Center at Children’s Hospital of Philadelphia.


Aluminum is everywhere. It is commonly found in food, health-and food-related products, water, infant formula and even breast milk. And for over 75 years, very small amounts of aluminum (aluminum gels or aluminum salts) have been added to some vaccines as “adjuvants” to help boost the body’s immune response. Without the use of these aluminum gels/salts in these vaccines, healthcare providers would need to give more doses of the vaccine or there there would be less immunity provided by the vaccine, and therefore less protection from the disease.

Watch Now: Can you explain why adjuvants, like aluminum, are in some vaccines?

Learn more about aluminum in vaccines from the Vaccine Education Center at the Children’s Hospital of Philadelphia.


Adjuvants, such as aluminum, are added to certain vaccines to help trigger a better immune response from your body. Without the adjuvant, we would need to give more doses of a vaccine or  the vaccine would give us less immunity protection from the disease.

Watch Now: Can you explain why adjuvants, like aluminum, are in some vaccines?

Studies have shown there is no connection between adjuvants and the development of autoimmune diseases.

Residual Antibiotics

Antibiotics are added to some vaccines to prevent the growth of bacteria during the vaccine manufacturing process and storage of the vaccine. No vaccine produced in the United States contains penicillin.

Learn more about how vaccines are made.

Egg Protein

Some vaccines, like MMR and some some flu vaccines, are prepared in eggs which means that some egg proteins are present in the final vaccine product. The egg proteins help manufacturers to grow enough of the virus or bacteria needed to make the vaccine. Based on scientific evidence, the American Academy of Pediatrics (AAP) states that the MMR vaccine can be safely given to all patients with egg allergies, including patients with a history of severe, generalize anaphylactic reactions to eggs.  AAP also states that “children with egg allergy can receive influenza vaccine with no additional precautions than those considered for any vaccine.” 

Additionally, the American Academy of Allergy, Asthma & Immunology (AAAAI) states “Studies show that flu vaccines can be safely administered to egg allergic individuals.” If you or your child are allergic to eggs, make sure to tell your doctor or healthcare provider before getting vaccinated.


Some vaccines contain gelatin to protect them against freeze-drying or heat during the transportation and storage process. People with severe allergies to gelatin should talk to their doctor or healthcare provider before getting vaccinated.

Religious leaders of the Muslim and Jewish communities have approved the use of vaccines containing gelatin.


You may have heard that vaccines contain products such as antifreeze. This is not true. Antifreeze typically contains ethylene glycol, an unsafe and highly toxic (poisonous) component, or propylene glycol, a safer and less toxic option to ethylene glycol. Neither of these members of the glycol family of compounds is used in vaccines. In vaccines, polyethylene glycol is used to inactivate the virus in some influenza vaccines and is also used to purify other vaccines. Polyethylene glycol is approved by the FDA and considered non-toxic for medical and other uses.* It is used in a variety of products including skin cream, toothpaste, lubricating eye drops, laxatives, and as an anti-foaming agent in food. It is also used as an irrigating solution in surgical procedures.

Victor O. Sheftel (2000). Indirect Food Additives and Polymers: Migration and Toxicology. CRC Press, 1114-1116.

Sources and Additional Resources

Vaccine Ingredients Q&A (Handout in English and Spanish) – Vaccine Education Center at Children’s Hospital of Philadelphia.

Learn more about vaccine ingredients on our website.