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Pregnant, breastfeeding or trying to conceive? Answers to your COVID-19 vaccine questions

Answers provided by Dr. Jerome Leis and Dr. Art Zaltz. Dr. Leis is the Medical Director of Infection Prevention and Control at Sunnybrook and Dr. Zaltz is Chief of the DAN Women & Babies Program at Sunnybrook.

I’m pregnant. Should I receive the COVID-19 vaccine?

Dr. Zaltz: Most pregnant patients will benefit greatly from the protection provided by receiving a COVID-19 vaccine, including the new bivalent vaccine. If you have any questions or concerns, I urge you to speak with your obstetrician, midwife or family doctor. They will review the risks and benefits of COVID-19 vaccination to help you decide what is right for you.

Are pregnant patients at increased risk of complications from COVID-19?

Dr. Leis: The COVID-19 pandemic has disproportionately affected pregnant patients, who are at higher risk of severe COVID-19 disease compared to similarly aged non-pregnant individuals. Canada’s National Advisory Committee on Immunization (NACI) has recommended mRNA vaccines for pregnant people since early 2021. A new study found that COVID-19 mRNA vaccines are safe to use in pregnancy, and that pregnant people experienced lower rates of health events post-vaccination than similarly aged, non-pregnant vaccinated people.

Why weren’t individuals who are pregnant included in the initial clinical trials for the COVID-19 vaccines?

Dr. Zaltz: Clinical trials for the COVID-19 vaccines deliberately did not include pregnant patients. It’s common practice for clinical trials to exclude those who are pregnant, with concerns about fetal development cited. A recent study suggests that the COVID-19 vaccine booster or third dose was well tolerated among pregnant and lactating individuals. The American College of Obstetricians and Gynecologists recommends that pregnant, and recently pregnant people up to 6 weeks postpartum, receive a bivalent mRNA COVID-19 vaccine booster dose following the completion of their last COVID-19 primary vaccine dose.

I’ve heard that those who are trying to get pregnant shouldn’t receive the COVID-19 vaccine as it affects fertility. Is that true?

Dr. Leis: There is no scientific evidence that the vaccine impacts fertility. This is not a concern at all. It is true that at a population level, one study found a less than one-day change in the onset of menstruation. This is not unexpected given that we know that stressors such as an immune response can have a small effect on hormone cycles. These authors concluded that their findings were reassuring since they found no clinically meaningful change in menstrual cycle length.

I’m considering starting fertility/IVF treatments – is it okay to get vaccinated?

Dr. Zaltz: A recent Israeli study published in Fertility and Sterility found that COVID-19 vaccine does not affect IVF success rates. Researchers at the Sheba Medical Center found no difference in the rate of pregnancy between vaccinated and unvaccinated test groups. The mRNA vaccines have no negative effect on frozen-thawed embryo transfer, which is the core practice of IVF (In-Vitro Fertilization).

I’m pregnant and curious if the antibodies generated from the COVID-19 vaccine will be delivered to my baby?

Dr. Zaltz: We do know that in general, antibodies cross the placenta to offer protection to the fetus. For this reason, vaccines like the influenza shot are recommended during pregnancy. A recent study shows COVID-19 vaccination during pregnancy was associated with lower risks of neonatal intensive care unit admission, intrauterine fetal death, and maternal COVID-19 infection.Vaccine-generated antibodies were also present in all umbilical cord blood and breast milk samples taken from the study, showing the transfer of antibodies from mothers to newborns.

Are there any guidelines for timing to receive the vaccine in pregnancy (ie: first, second or third trimester?)?

Dr. Zaltz: The COVID vaccine can be administered at any point during pregnancy and ideally the sooner the better. You may recall that when they were first approved and distributed these vaccines needed to be given at least 14 days before or 14 days after any other vaccination. This restriction is no longer in place. COVID-19 vaccination, including the new bivalent vaccines, can be given at the same time as important vaccines like influenza, and Tdap (tetanus, diphtheria, pertussis) that are routinely recommended during pregnancy.

Can I get the vaccine if I’m pregnant and have allergies?

Dr. Leis: In the majority of cases, people with allergies can receive the vaccine. There are two exceptions:

People who have had an allergic reaction to polyethylene glycol, or PEG. PEG is a component in the vaccine that can elicit an allergy response. It is a very rare allergy, but it is important that people who have this allergy do not receive the vaccine.
Anyone who has had a reaction to the first dose of the vaccine should not receive the second dose.