What to know about COVID vaccines, fertility, and pregnancy
May 2, 2021 Being Well
E. Rosalie Li, Interdisciplinary Public Health Johns Hopkins Bloomberg School of Public Health
- What to know about COVID vaccines, fertility, and pregnancy
- Questions about vaccines and women’s health
- Could cycle irregularities be related to the vaccine?
- New data on the vaccine and pregnancy reassures.
- We found Zika in 1947 but did not recognize its connection to microcephaly until 2016.
- Will the mRNA affect the placenta?
- Why don’t we know if vaccines cause menstrual irregularities?
- No, the HPV vaccine does not cause infertility.
Questions about vaccines and women’s health
Let’s discuss Covid vaccines, whether they affect menstrual cycles, and infertility claims.
- Can the vaccine make you infertile?
- Can vaccinated women somehow affect unvaccinated women’s cycles?
- Can the vaccine affect the vaccinated woman’s cycle?
No, No, and Maybe. Here’s what isn’t happening:
- First, it is impossible for vaccinated women to shed the SARS-CoV-2 virus due to the mRNA vaccine. This would mean they cannot spread the virus to unvaccinated women.
- mRNA vaccines do not contain a whole virus, not even inactivated. Thus, there is nothing to “shed.”
Could cycle irregularities be related to the vaccine?
Yes, there may be some association. It could also be that many women are hearing it and ascribing irregularities they would have had regardless of the vaccine. Let’s more closely at explanations.
The endometrium has its own immune environment. Put another way, it’s part of the immune system. What does a vaccine affect? The immune system.
A Covid-19 infection can affect menstrual cycles, so it’s not shocking that building immunity could also. It’s possible that cycle irregularity, like feeling achy, tired, or running a fever after a vaccine, may be a response to the vaccine.
It also might not be. What affects the immune system could plausibly affect the endometrium. Immune dysfunction is something that plays a role in endometriosis.
Locking down the uterus via the endometrium makes sense because, like the brain, the reproductive system is immune-privileged. This means the body hesitates to bring in the cavalry when there is an infection to avoid hurting you. That also means if a virus does make it to the brain or your reproductive system, it may hide there indefinitely.
It’s something to consider. What this does not mean:
- This does not show that vaccines can cause infertility any more than it means it will cause an ever-lasting fever. There’s no logical reason to suspect that.
- We should not confuse this with meaning that it would affect pregnancy in progress because we haven’t found that in large-scale studies. The uterus is a changing environment; while pregnant, it differs considerably from when it is vacant.
- This also doesn’t mean anyone is lying or being dishonest necessarily. Anything that follows a vaccine may be reported to VAERS, Vaccine Adverse Event Reporting System, but it’s not proof the vaccine had anything to do with what was reported.
Many people misunderstand the data in VAERS and repeat their misinterpretations, but VAERS cannot and has never been intended to show causality. Anyone anywhere may submit anything.
The chief problem with the VAERS data is that reports can be entered by anyone and are not routinely verified. To demonstrate this, a few years ago I entered a report that an influenza vaccine had turned me into The Hulk. The report was accepted and entered into the database. — James R. Laidler, M.D.
The CDC understandably contacted Dr. Laidler. They asked if he would permit them to remove it. He did as the experiment had served its purpose but had he said no, the claim that his vaccine turned him into The Hulk would still be in VAERS right now. That would not make it true.
New data on the vaccine and pregnancy reassures.
Reports from over 35,000 US women who received mRNA vaccines while pregnant show comparable rates of miscarriage, premature birth, and other complications compared to before the pandemic. These preliminary results reflect women who received either the Moderna or Pfizer mRNA shots while pregnant.
Their rates of miscarriage, premature births, and other complications were comparable to those observed in published reports on pregnant women before the pandemic.
Critically, we know that pregnant women are more likely to fall seriously ill if infected with Covid, and while we haven’t found the virus affecting babies in utero, it may affect them in ways that are harder to detect. It’s possible; if so, the possible consequences could be extreme.
- The omission bias may lead women not to vaccinate because they perceive it as a lower risk. It’s not. Recent history gives us ample reason to vaccinate.
- We have yet to find a vaccine that has harmed pregnant women. The theoretical risk of transmitting a virus to the baby means most recommendations say to avoid live-virus vaccines, but it’s based on the possibility, not history.
- This makes the argument for mRNA vaccines all the more compelling since giving the baby the virus is impossible. No virus “killed,” inactivated, or otherwise exists in the vaccine.
It contains enough for the immune system to recognize the real deal should it invade. It’s like showing law enforcement a mug shot. While some mug shots are scary, they cannot attack you.
The fact that no other vaccines have been shown to harm the baby and that no vaccine is totally contraindicated in pregnancy should be weighed against the massive number of viruses that have the ability to harm the baby or the mother. Especially we should reflect on viruses that may have consequences that we won’t detect for years or even decades.
We found Zika in 1947 but did not recognize its connection to microcephaly until 2016.
In 2016 we realized it was causing neurological conditions, including microcephaly. There were no large-scale outbreaks where a rare consequence of infection might have been noticed before that. Other viruses can cause cancer, long-term post-viral illness, and immune amnesia.
It took us centuries to determine that measles increased the risk of low birth weight, miscarriage, stillbirth, and maternal death. Measles also causes immune system “amnesia,” increasing the risk of a child dying of later infection.
- 5X as likely to be admitted to an ICU
- 3X as likely to have a severe infection
- had a 60–97% increased rate of preterm birth and
- a 76% greater chance of preeclampsia or eclampsia
- Breastfeeding didn’t appear to transmit the virus.
Studies show the Covid vaccine is safe for pregnant women. The history of vaccines shows an absence of vaccines found to cause harm in pregnant women. At the same time, Covid infection can be more severe in pregnant women, cause stillbirth, and be potentially fatal in newborns.
Will the mRNA affect the placenta?
This idea came from someone who was unfamiliar with the subject matter reading a study. When you study something long-term, you tend to know more about it than others. People who haven’t spent the time know less and are more likely to misinterpret or misunderstand information.
- Fact check: Available mRNA vaccines do not target syncytin-1, a protein vital to successful pregnancies
Why don’t we know if vaccines cause menstrual irregularities?
Most vaccinations are done by the time we enter puberty. Except for Gardasil, there aren’t many women receiving a completely new vaccine for a pathogen against which they have no immunity. We don’t normally track it in trials because it hasn’t been an area of concern.
- A study on Gardasil in Japan looked and menstrual irregularity but did not find a statistically significant number of women reporting it. There were women reporting changes but weren’t out of step with the number reporting in the non-vaccinated group.
- Some historical studies suggested the phase of a menstrual cycle affected how the body responded to the vaccine. That said, it should be moving forward.
It is plausible that menstrual cycle changes could be a common side effect that we didn’t know about, given research bias toward males and the age at which we give most vaccinations. If it was a possible common side effect, we might not know for sure, and plenty of plausible ways this could happen exist — none of which are concerning.
No, the HPV vaccine does not cause infertility.
This misinformation originated in the early 1990s and popped up again in 2014 from Catholic clergy in Kenya. They suggested a contraceptive vaccine explained why WHO was changing vaccination schedules. That was incorrect. A 1995 white paper detailed the damage misinformation did to global vaccination efforts.
The schedule change had to do with getting girls vaccinated before they had their first baby because death from tetanus is a real threat.
Four countries saw rates of tetanus vaccination drop after pro-life groups began telling locals that they were being used as “guinea pigs.”
“Rumors have circulated recently in Mexico, Tanzania, Nicaragua and the Philippines that WHO and UNICEF are using women as guinea pigs to test a contraceptive vaccine given to them under the guise of tetanus toxoid vaccine. These rumors, apparently initiated by so-called pro-life’ groups, are completely untrue. The vaccines do not contain contraceptive vaccines or any other substance which interferes with fertility or pregnancy and their labeling accurately describes their actual contents. The false claims made by these groups have had an adverse impact on immunization programs in all four countries.” — Julie Milstien, P. David Griffin & J-W. Lee (1995)
Either way, the priests and anti-abortion groups handled their sincere concerns in an irresponsible way. The accusations were false. Still, babies died because of those claims. Neonatal tetanus caused around 25% of infant death in developing countries in the 1990s, when misinformation led to a drop in vaccination rates.