With both COVID-19 vaccines now approved by the FDA to be delivered and administered across the country, there are still many people with questions. None more so than the trying to conceive, pregnant, and breastfeeding population. So we thought we’d help out with this guide to the vaccines.

Now before we start, I’m going to state the obvious: I am an OBGYN. That means I am not a virologist, immunologist, or infectious disease specialist. However, I am a trained medical professional who can read research papers and clinical trials to assess how significant their findings are.

My goal here is to break down the science behind these vaccines so that you are more able to make an informed decision about whether or not the vaccine is right for you and your family. Below are some frequently asked questions about the vaccines in general and about the vaccines as they relate to trying to conceive all the way to postpartum. 

Why should I get a vaccine if COVID-19 has a 99% survival rate?

What many don’t realize is that surviving COVID-19 is not the same as being totally fine afterward. Symptoms can persist for months and even young, healthy people can be sick for a long time. COVID-19 can damage your lungs, heart, brain, and other organs. Among other things, COVID-19 has been shown to do the following:

  • Damage to the cardiac muscles, seen in the imaging of patients months after COVID-19 infection (even with only mild symptoms)

  • Seizures

  • Strokes

  • Guillain-Barre syndrome (causes temporary paralysis, yikes)

  • Pneumonia with long-term breathing problems

  • May increase the risk of developing Parkinson’s and Alzheimer’s

  • And of course, there’s always the risk of hospitalization, intubation (breathing tube), and death

How do the COVID-19 vaccines work?

Both the Moderna and Pfizer vaccines are injected into the muscles of the upper arm and use mRNA technology (more on that later). The mRNA vaccines in this casework by providing our cells with instructions for making a piece of “spike protein” that is found on the surface of the virus that causes COVID-19. This is harmless because it is made by our own bodies and not the actual COVID-19 virus. Once a muscle cell has used the instructions to make the spike protein piece, it breaks down the instructions and disposes of them. 

The cell then displays that protein piece on its surface. The immune system sees that piece, recognizes that it doesn’t belong, and gets to work making antibodies against it. Basically, our immune system is Damian in Mean Girls when he shouts “she doesn’t even go here!” 

Once those antibodies have been made, our body has now learned how to fight off a future infection by the actual COVID-19 virus. Pretty cool, right?

The benefit of this vaccine, just like any other vaccine, is that those who get it now have immunity against the disease in question without ever having to risk the serious consequences of the actual disease. 

What is mRNA technology?

You may have learned about this in high school biology. mRNA, or messenger RNA, produces instructions for cells for how to make proteins that can treat or prevent disease. mRNA technology was originally discovered over 30 years ago with the first successful use in animals being published in 1990. It has been studied for vaccine use for almost 20 years. 

Researchers had been working on coronavirus vaccine since the SARS and MERS outbreaks until they ran out of funding. Early stage trials using mRNA vaccines have been done for the flu, Zika, rabies, and other bugs. 

What are the differences between the two vaccines? Which one is better?

The vaccines are overall very similar. One is manufactured by Moderna and one is by Pfizer. The biggest differences between the two vaccines are storage temperature and how they are administered, which are important for healthcare organizations, but not so much for those receiving the vaccine. It’s also not really an option to choose one vs. the other anyway because most facilities will stock only one of them depending on availability in that area and their ability to store the vaccine appropriately. 

Key differences:

FertiCalm App

$19.99
10% OFF

Labcorp OnDemand Women’s Fertility Package (Ovarian Reserve Test)

Discount Code: RESCRIPTED10
$179.00
25% OFF

LetsGetChecked Ovarian Reserve Test

Discount Code: RESCRIPTED25
$139.00
20% OFF

Binto Milkmaid | Lactation support gummies

Discount Code: rescripted20
$19.98

How effective are the vaccines?

They are both about 95% effective (Moderna = 94.5%, Pfizer = 95%).

What are the common side effects?

The side effects of a vaccine are considered part of the “immune response.” This is GOOD because it means your body is learning the information it needs to fight off the real infection if it ever happens. 

The idea is to have these shorter-term, manageable symptoms, rather than full-blown COVID-19. 

  • Injection site reaction

  • Fatigue

  • Headache

  • Muscle pain

  • Chills

  • Joint pain

  • Fever

Less than 1% of participants in both the vaccine and the placebo arm experienced serious adverse effects (that is at the same frequency as we see in the general population). For more data on adverse reactions, check here. 

Who should NOT get the vaccine?

Almost everyone should be able to get the COVID-19 vaccine; however, children younger than 16 years old were excluded from the trials and therefore cannot receive it. If you currently have COVID-19, wait until after your symptoms have cleared and you’ve come out of quarantine to vaccinate. There's no recommended minimum time between infection and vaccination. If you’ve had COVID-19 already, you can still get vaccinated.

The vaccines were shown to protect people with past COVID-19 infections from reinfection regardless of how severe their past case was.

Those with a history of vaccine allergies or other severe allergies can still get the vaccine but should be monitored closely immediately after receiving it. Immunocompromised individuals can also still get the vaccine but should speak to their providers before making that decision. 

Is it ok for me to get the vaccine if I’m trying to conceive?

Unless you fall into one of the buckets above or your provider tells you otherwise, then yes, it's safe to get the vaccine if you're TTC! The vaccines do not use any live virus, so there’s no reason to wait to try to get pregnant. Additionally, if you find out you’re pregnant between the first and second dose of your vaccine, it is safe to get the second dose. The risk of getting COVID-19 is far more severe than the risk of getting the vaccine. 

Is it safe to continue infertility treatments if I get the vaccine?

Yes! See above answer. There is no reason to delay IUI or IVF because of the vaccine. In fact, the ASRM COVID-19 Task Force encourages patients undergoing fertility treatment to receive vaccination based on current eligibility criteria.

Can I get the vaccine if I’m pregnant or breastfeeding?

The FDA Task Force has recommended that the decision to get the COVID-19 vaccine be a shared process between a patient and their provider. They do not recommend withholding the vaccine from patients who are planning to conceive, currently pregnant, or breastfeeding. These are in line with the recommendations from the Advisory Committee on Immunization Practices, Centers for Disease Control and Prevention, American College of Obstetricians and Gynecologists, and Society of Maternal Fetal Medicine. 

There were 23 pregnancies reported during the Pfizer trial, 12 of which were in the vaccine arm. Moderna reported 13 pregnancies, six of which were in the vaccine arm. Both trials reported adverse events in two of their pregnant patients—all of them were in the placebo arms (i.e., did not get a real vaccine).

Both trials reported adverse events in two of their pregnant patients—all of them were in the placebo arms (i.e., did not get a real vaccine).

Be the expert in you.

Take the Quiz


The right decision for you depends on a lot of factors, such as if you work in a high-risk healthcare setting. Talk to your provider about how to balance the lack of data on vaccine safety for the fetus, risks to pregnant people from COVID-19 infection, and your individual risk for infection and severe disease.

I read that the vaccine can cause a fever. Is that safe if I'm trying to conceive or pregnant?

Yes. In the clinical trials, the vaccines caused fever in about 14% of patients, usually after the second dose (Pfizer = 14.2%, Moderna = 14.8%). This side effect should not be a reason to defer vaccination in someone who is trying to conceive, pregnant, or breastfeeding. Studies have linked fever in the first trimester of pregnancy to neural tube defects; however, this risk is NOT significant in those who were taking the recommended dose of at least 400mcg of folic acid (folate) daily, so please make sure you are taking a prenatal vitamin! If you do develop a fever after getting the vaccine, take Tylenol to help reduce it.

Does the vaccine cause infertility or affect pregnancy outcomes?

No. Because the vaccines are not live, they are not thought to cause infertility, increased pregnancy loss, congenital anomalies, or stillbirth. The number of accidental pregnancies during the trials supports that fertility is not affected.  

How applicable is the data from these trials for Black people and other POC given the disproportionate effect on those groups?

Both trials had well over 30,000 participants (Moderna = 30,350, Pfizer = 43,448). 30% of US participants were from diverse backgrounds (meaning Black, Hispanic, Asian, and Native American), with 10% being Black. This is comparable to the general US population of which 13% are Black.  

As much as the American medical system has dismally failed this community in the past and as difficult as it may be to trust these vaccines, it is so important that BIPOC strongly consider immunization. The rate of death from COVID-19 infection is two to four times higher for BIPOC than it is for our white counterparts. Not getting a vaccine will simply compound the already higher rates of adverse effects, hospitalization, and death due to COVID-19 in these groups.  

I keep seeing stuff about how the vaccine will alter our DNA. Is that true?

Definitely not. Let’s think back to high school biology again for a second. RNA is not in the nucleus of the cell, only DNA is. So the mRNA involved in the vaccines never enters the nucleus of our cells to get anywhere near our DNA. Once our cells have learned what they need to from the mRNA, it breaks it down.

Don’t the vaccines have some unhealthy ingredients? I heard they contain aluminum, mercury, and food allergens like wheat or yeast.

False. Check out the ingredients list here for Pfizer and here for Moderna. 

Am I going to be forced to get the vaccine?

Absolutely not. This process should be a shared decision making between you and a provider you trust. A careful analysis of your personal risks is important in making sure that the safest option is recommended. 

For more information about the COVID-19 vaccines, check out the links below. And don’t forget to talk to your provider if you’re not sure what to do for you or your loved ones. 

*This article was originally published on Natalist.com here.

Dr. Marieme Mbaye is a Medical Advisor at Natalist and an obstetrician and gynecologist focused on giving patients the tools they need to take charge of their health. She has a wide range of surgical and procedural experience, including robust robotics and laparoscopic training. She received her MD from the University of Tennessee Health Science Center, and her BS from Yale University.