Vaccines in Pregnancy: What You Should Know

Influenza vaccine
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When seemingly harmless things like cold cuts and soft serve ice cream suddenly become off-limits, the world can be a downright scary place for a pregnant woman. The many do's and don'ts can leave you feeling cautious about everything you put in your body—including getting vaccinated. But like prenatal vitamins and exercise, vaccines are an important part of a healthy pregnancy.

Recommended Vaccines

Two vaccines are recommended for pregnant women during each and every pregnancy: the flu shot and Tdap.

Both are important to maintain not only the health of the mom during and after pregnancy but also to protect the health of the baby in the womb and during those first few months of life.

The Flu Shot

Between 12,000 to 56,000 people in the United States die from the flu every year—more than all other vaccine-preventable diseases combined—and pregnant women are especially at risk. Because of the way the human body changes during those critical 40 weeks, pregnancy leaves you more vulnerable to infection from viruses like the flu, and if you do fall ill, you're more likely to be hospitalized or die as a result.

While there are several ways you can protect yourself from getting sick while pregnant—such as frequent hand-washing and healthy eating—the single best way to protect yourself from flu is by getting vaccinated. The best time to receive the flu shot is in early fall before the flu season is in full swing, regardless of where you are in your pregnancy.

Getting the flu shot during pregnancy also protects newborns. Infants don't receive their first dose of the flu vaccine until they are at least 6 months old. Until that time, they are vulnerable to a severe infection. Babies whose moms were vaccinated during pregnancy, however, are significantly less likely to be hospitalized as a result of flu during the first six months of life.

Protecting yourself during pregnancy lowers the chances you'll pass the virus onto your baby, but your baby also receives passive immunity from you while in the womb, which will help them fight off the virus if they are exposed during their first few months.

Tdap Vaccine

The same is true for the Tdap—or tetanus, diphtheria, and acellular pertussis—vaccine. While pertussis in adults is often very mild, pertussis in infants can be devastating. Babies don't get their first dose of pertussis vaccine until 2 months old, but those first eight weeks are a vulnerable time for newborns, especially if they become infected with pertussis. About half of all infants under one year with pertussis are hospitalized, and about 20 die each year as a result of the infection—most are under 3 months old. Pregnant women who get Tdap during the third trimester pass on protective antibodies to their babies in the womb, and those antibodies help to protect newborns until they can begin the pertussis vaccination series themselves.

Other Vaccines

Other vaccines might also be recommended if you intend to travel outside of the United States during your pregnancy, or if you have certain risk factors. Mothers with chronic liver conditions might be encouraged to get the Hepatitis A vaccine, for example, while others planning to travel to certain parts of Africa might need to be vaccinated against meningococcal disease.

Not all travel vaccines have been shown to be safe for pregnant women, however, which is why it's important to talk to your healthcare provider or visit a travel clinic before receiving vaccines.

Evidence of Safety

No vaccine—or any medical product—is 100 percent safe. But side effects from vaccination are almost always mild and temporary, and severe effects like a strong allergic reaction are rare. The important question asked by those who make the vaccination schedule is whether the benefit of vaccination outweighs any known risks. And given the severe risks associated with diseases like flu and pertussis, research has made a strong case for maternal vaccination.

One study in the journal Vaccine made headlines when researchers found a possible link between the flu vaccine and miscarriage, sparking some concern among pregnant women about whether they should be vaccinated against the flu. While this is understandably alarming, the Centers for Disease Control and Prevention—who funded the study—was quick to point out that pregnant women should still be vaccinated against the flu. The study didn't determine that the vaccine caused miscarriage, only that women who miscarried were more likely have received the flu vaccine in the 2010-2011 and 2011-2012 flu seasons.

Many things can lead to pregnancy loss, and while the results certainly warrant further investigation, more research is needed. The study itself is something of an outlier, as several prior studies showed the flu vaccine to be safe when given to pregnant women and effective at preventing flu.

The safety of the Tdap vaccine during pregnancy has also been well documented, and studies show it to be safe and effective at protecting mom and baby from pertussis. Like the flu vaccine, the most common side effects are arm soreness, fatigue, and fever. Severe allergic reactions to the vaccine are extraordinarily rare, especially in adults.

Both the flu shot and the Tdap vaccine can be given safely at the same time or at separate visits, and it doesn't matter how recently you received a tetanus shot. 

Some online forums and websites have posted misleading or inaccurate information about the ingredients in vaccines, leading some moms to worry about their safety—specifically, singling out thimerosal, which is an ethylmercury-containing compound sometimes used to keep vaccines safe from contamination. Very few vaccines use this component, and studies researching its effect show no evidence of harm and no increase in the baby's risk for autism. If you would still prefer to avoid thimerosal, however, there are thimerosal-free versions of the flu vaccine available, and it is not used in the creation of the Tdap vaccine.

Vaccines to Avoid

While vaccines can be beneficial, some should be avoided—if possible—during pregnancy. Vaccines that use live but weakened viruses, for example, such as the MMR or chickenpox vaccines, carry a theoretical risk to the baby and therefore shouldn't be given to pregnant women.

If you get vaccinated with one of these vaccines before you learn you're pregnant, don't panic. The recommendation to avoid them is largely just a precaution. Studies looking at women who were inadvertently vaccinated with live vaccines during pregnancy didn't find any evidence of harm to the babies.

Even though you shouldn't be vaccinated against these diseases during pregnancy, you could still become infected and experience severe complications as a result. If you're planning to get pregnant—but aren't pregnant yet—be sure to talk to your healthcare provider about what vaccines you should get beforehand so that you're protected throughout your pregnancy. This is especially important for the rubella vaccine, as rubella infection during pregnancy can cause birth defects and miscarriage.

Vaccines for Friends and Family 

Expecting mothers aren't the only ones who should get vaccinated. Other caregivers, siblings, grandparents, and anyone else who will be interacting with the baby during the first few months of life should also be fully up-to-date on all vaccines—including the annual flu shot. If possible, visitors should get their vaccines at least two weeks before meeting the baby so that they have time to develop sufficient protection against the diseases.

Asking loved ones to get vaccinated can be awkward, especially if they have expressed hesitancy toward vaccination in the past. Resources are available from parent-led advocacy groups like Voices for Vaccines to help guide you through the conversation if you experience or anticipate pushback. While the prospect of confrontation can be daunting, it's an important step to keep your baby as safe as possible, as many diseases—including flu and measles—can be spread even if symptoms are mild or absent. Not all vaccines are 100 percent effective, which is why everyone who can be vaccinated safely should be vaccinated.

A Word From Verywell

Getting vaccinated during pregnancy is an important way to protect your health and the health of your growing baby. If you have any questions or concerns about vaccine side effects or risks during pregnancy, talk to your healthcare provider.

Sources: 

Centers for Disease Control and Prevention. Guidelines for Vaccinating Pregnant Women

Centers for Disease Control and Prevention. Flu Vaccine Safety and Pregnancy

Centers for Disease Control and Prevention. Maternal Vaccines: Part of a Healthy Pregnancy

Centers for Disease Control and Prevention. Updated recommendations for use of tetanus toxoid, reduced diphtheria toxoid and acellular pertussis vaccine (Tdap) in pregnant women and persons who have or anticipate having close contact with an infant aged <12 months—Advisory Committee on Immunization Practices (ACIP), 2011MMWR Morb Mortal Wkly Rep 2011;60:1424–6.

Grohskopf LA, Sokolow LZ, Broder KR, et al. Prevention and Control of Seasonal Influenza with Vaccines: Recommendations of the Advisory Committee on Immunization Practices — United States, 2017–18 Influenza Season. MMWR Recomm Rep 2017;66(No. RR-2):1–20.

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