Let's Talk About the Vaccines, Menstrual Cycles, and Claims about Fertility

Can the vaccine make you infertile? Can vaccinated women somehow affect unvaccinated women’s cycles? Can the vaccine affect the vaccinated woman’s cycle?

Let's talk about the vaccines, whether they can affect the menstrual cycle, 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

The first thing I should clarify is that it is impossible for vaccinated women to shed anything, as a consequence of being vaccinated, to unvaccinated women.

If anything it's the other way around, but honestly, this is a silly idea that we are giving the power to scare us. The mRNA vaccines do not contain the virus at all, not even inactivated. There is nothing to "shed."

Let me say it again.

The mRNA vaccines do not have the virus in them and cannot lead to shedding of any kind. You also cannot get Covid from mRNA vaccines as a consequence.

Could Cycle Irregularities Be Linked to the Covid Vaccine?

Yes, there may be some association. It could also be that a lot of women are hearing it and ascribing irregularities they would have had anyhow to the vaccine. Let’s look at possible reasons.

The endometrium has its own immune environment. Put another way, it's a part of the immune system.

What does a vaccine affect? The immune system. Covid-19 infection itself can affect menstrual cyclesso it’s not shocking that building immunity could as well. It's possible that cycle irregularity, like feeling achy, tired, or running a fever after a vaccine, maybe 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 basically 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.

Ebola did this recently. Someone who contracted Ebola years ago infected a sexual partner and the genomic sequencing shows it’s the virus from years ago, shown in the graph far removed from the 2015 outbreak. Something to consider.

What this does not mean:

  1. This would not be evidence the vaccine can cause infertility any more than it means it will cause an ever-lasting fever. There's no logical reason to suspect that.

  2. 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 and while pregnant it differs considerably from when it is vacant.

  3. 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 to make claims about vaccines that are terrifying, 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 Covid-19 Vaccine and Pregnancy Reassuring

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 do 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 and if so, the possible consequences could be extreme. I don’t want to scare any pregnant women, but in this case, the truth is scary and you deserve the truth. We need to tell women this.

The omission bias may lead women not to vaccinate because they perceive that as the lower risk. It’s not. Recent history gives us ample reason to vaccinate, especially given that we have yet to find one that pregnant women must avoid. The theoretical risk of transmitting a virus to the baby means most recommendations say to avoid live-virus vaccines.

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 only contains enough for the immune system to recognize the real deal should it attempt to invade the body. It’s like a mug shot. While some mug shots are a little 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 bring about consequences down the road that we wouldn’t know about right now.

Zika was discovered in 1947.

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 figure out measles increased the risk of low birth weight, miscarriage, stillbirth, and maternal death. Measles also causes immune system "amnesia" increasing the risk a child dies of a later infection.

Pregnant women with COVID-19 compared with those not infected were:

Given the real studies of women receiving this vaccine and the history of vaccines showing no harm in pregnant women, the Covid infection is easily the greater threat and concern for the mother and baby.

If I were pregnant right now, I would get the mRNA vaccine without question.

Will the mRNA Target a Protein in the Placenta?

This idea came from someone who was unfamiliar with the subject matter reading a study. I know no one wants to believe this, but when you study something long term you tend to know more about it than other people. People who haven't spent the time, know less.

This should be relatively uncontroversial, methinks.

Why Don’t We Know If Vaccines Can Affect Your Cycle?

Most vaccinations are done by the time we enter puberty. With the exception of Gardasil, there aren't large numbers of 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 issue.

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 they weren't out of step with the number reporting it in the non-vaccinated group.

That said, it should be moving forward but women as the subject of research is another topic for another day. There were some historical studies that suggested the phase of a menstrual cycle affected how the body responded to the vaccine. 

The truth is it’s completely believable that this could be a common side effect that we didn’t know about, given research bias toward males. 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.

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 they weren't out of step with the number reporting it in the non-vaccinated group.

No, Gardasil 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.

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.

Over 550,000 babies were dying per year from tetanus, at the time the study lamenting the misinformation was published. Tetanus deaths accounted for as much as 25% of all infant deaths in the developing world.

“Rumours 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 rumours, 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 labelling accurately describes their actual contents. The false claims made by these groups have had an adverse impact on immunisation programmes in all four countries.”

Julie Milstien, P. David Griffin & J-W. Lee (1995)

Either way, the priests and pro-life groups were unqualified to make these assertions, could have handled sincere concerns in a more responsible way. The accusations were false.

That did not stop foreign disinformation efforts from amplifying the rumor over the past 25 years. This misinformation and the fear it caused provided the basis for one of the most enduring pieces of misinformation.

None of this stopped the harm the rumor did to vaccination efforts among those most likely to die or lose their baby.

Perhaps the priests and groups were sincere and well-meaning, but this is a testament to why we do not make claims lightly and why we handle them professionally. The fear and outrage generated in multiple countries were avoidable and recklessly stoked.

Just as someone might accidentally hit someone with a car, the victim is no less dead if we didn’t mean it. No remorse can bring the babies that died back to their mothers. Some of them would be adults today had they lived.

Neonatal tetanus caused as much as 25% of infant death in developing countries in the 90s.

Overall, it's not surprising that an immune response would affect the menstrual cycle. I'm quite sure the list of things that do not affect cycles would be shorter than those that do. That list is not the same as the list of things that could cause a woman to miscarry or have a stillbirth.

Personally, I have had both doses of the Pfizer mRNA vaccine, and suffice to say, it’s not something over which I'm losing sleep. If I saw any evidence the vaccines weren’t, I would be the first person on every horn on every social media platform because I care about my friends, family, readers, and people I don’t know.

You don’t get into public health unless you’re comfortable making less than you would in almost any other field. Generally, concern for the public is the motivation, which makes it rather unlikely an entire field would cooperate with unethical and potentially harmful vaccinations.

Yes, when I hear these stories I feel that fear too.

Sometimes we feel fear when it doesn’t make sense. When I see an optical illusion, I know what my brain is telling me is wrong. That’s the reason we find illusions so entertaining.

We delight in exploiting our brain’s buggy interpretation of the world, but this phenomenon happens far more often than when we look at trippy graphics. Often, we aren’t aware that it’s happening and that can lead us to make poor choices or irrational decisions that feel right.

Let’s do an experiment, shall we? Close your left eye and just focus your right eye on the tiny static circle on the left of the screen. At some point, the big circle will disappear as it crosses your blind spot‘. If you can’t see this effect, it means you’re sitting too close/far from your monitor. Try sitting closer/further to the screen and repeat the test.

Have you found your blind spot? If so, you likely know the big black dot is still there even though it disappears from your vision. You know what your brain is telling you is wrong. If you didn’t before, you now know your brain can mislead you about reality.

The fear that I feel when I hear outlandish rumors and even some of the more believable ones doesn’t tell me anything about reality. It feels real just like the dot truly disappears from my sight, just like the red swirls move. I know neither is real.

Please know, I’m not at all dismissing your justifiable fear and concern because I know it can feel every bit as unpleasant as if it were a true threat. When I feel fear over the idea that the vaccine could make me infertile, it’s a disappearing dot. It’s a spinning swirl.

It’s terrifying, but the threat isn’t real.