What are vaccines?

Vaccinations or immunizations are shots you get to protect you from certain diseases.

The story of vaccines did not begin with the first vaccine–Edward Jenner’s use of material from cowpox pustules in 1796 to provide protection against smallpox. Rather, evidence exists that the Chinese employed smallpox inoculation (or variolation, as such use of smallpox material was called) as early as 1000 CE. It was practiced in Africa and Turkey before it spread to Europe and the Americas.

Over the next 200+ years, many more vaccines have been developed to address and prevent many infections.

Why are vaccines important during pregnancy?

The best time to talk about vaccinations is during a visit with your doctor before you get pregnant. If you get vaccinated before pregnancy then you and your baby are protected during pregnancy. Certain vaccinations are safe during pregnancy while others are not safe and are contraindicated.

While we should be more cautious giving certain vaccines in pregnancy, there is no evidence that any vaccine which is given during pregnancy, whether intentionally or not, can harm the fetus.

Your doctor may tell you that the benefits of getting vaccinated outweigh potential risks if all of the following are true:

• You are very likely to be exposed to a particular infection.
• The infection would pose a serious risk to you or your baby.
• The vaccine is unlikely to cause harm to you or your baby.
• If you are at an increased risk for infection, your doctor may suggest that you receive a vaccination that generally isn’t recommended during pregnancy.

Here are some examples of people who are often at increased risk of infection:

• Those who work in healthcare facilities
• Those who are traveling to areas where the infection is common
• Discuss each vaccine with your health care provider on a case-by-case basis and carefully weigh the risks and benefits of the protection that the vaccination will provide.

The US Department of Health and Human Services recommends the following vaccines preconception before pregnancy:

• Influenza/Flu
• HPV Human Papilloma Virus
• MMR Mumps Measles-Rubella
• Tdap
• Varicella/Chickenpox
• Hepatitis B if you are at risk
• Pneumococcus vaccine (if indicated eg smoker, diabetes, asthma)
• COVID-19 vaccine

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From: ACOG

Vaccines that are recommended during pregnancy

• tDap Tetanus-Diphtheria/Pertussis
• Influenza (Recommended to all pregnant women)
• COVID-19 vaccines

Vaccines that may be safely administered during pregnancy 

• Hepatitis B
• Rabies
• Inactivated polio
• Meningococcal
• tDap Tetanus-Diphtheria/Pertussis
• Influenza (Recommended to all pregnant women)

Vaccines that should not be given during pregnancy

• Mumps-Measles-Rubella
• Varicella (chickenpox)
• Yellow fever (may be considered if travel to the high-risk area is unavoidable)
• HPV Human Papilloma Virus
• BCG
• Vaccinia

Vaccines without available safety data during pregnancy

• Hepatitis A (immune globulin probably preferable)
• Typhoid (the injection with Typhim Vi may be safer since it's inactivated while the other typhoid vaccine is oral and has live attenuated bacteria)
• Japanese encephalitis (avoid travel to high-risk areas)

The risk to a developing fetus from vaccination of the mother during pregnancy is primarily theoretical. No evidence exists of risk from vaccinating pregnant women with inactivated virus or bacterial vaccines or toxoids. Live vaccines pose a theoretical risk to the fetus, but studies have shown no significant problems in pregnant women who received these vaccines. There is no recommendation to induce an abortion if you received these vaccines in pregnancy inadvertently.  

Benefits of vaccinating pregnant women usually outweigh potential risks when the likelihood of disease exposure is high, when infection would pose a risk to the mother or fetus, and when the vaccine is unlikely to cause harm. Generally, live-virus vaccines are contraindicated for pregnant women because of the theoretical risk of transmission of the vaccine virus to the fetus. If a live virus vaccine is inadvertently given to a pregnant woman, or if a woman becomes pregnant within 4 weeks after vaccination, she should be counseled about the potential effects on the fetus. Vaccination is not ordinarily an indication to terminate the pregnancy. Whether live or inactivated vaccines are used, vaccination of pregnant women should be considered based on risks versus benefits (i.e. the risk of the vaccination versus the benefits of protection in a particular circumstance).

(From the CDC)

The following table may be used as a general guide:

Recommended during pregnancy

• Hepatitis B 
• Influenza (Inact.) 
• Tetanus-Diphtheria - Pertussis (Tdap) 

Safe if indicated

• Hepatitis A
• Meningococcal (MCV4) 
• Pneumococcal 
• Polio (IPV) 
• Anthrax 
• Japanese Encephalitis 
• Meningococcal (MPSV4) 
• Rabies 
• Typhoid (Parenteral) 
• Yellow Fever

Not recommended during pregnancy

• Influenza (LAIV)   
• MMR 
• Measles  
• Mumps  
• Rubella  
• Varicella  
• BCG 
• Vaccinia 
• Zoster 
• HPV  - Human Papilloma Virus
• Typhoid (oral)