The Covid Vaccine May Affect Your Period — But No, It Doesn’t Cause Infertility

Recently, a friend texted, concerned that the COVID-19 vaccine made her infertile. Her period was late, she said, and others had (anecdotally) reported the same on Twitter. While I could technically relate — I too experienced strange period symptoms after mine — I was shocked by the leap from irregular periods to full-fledged pregnancy problems. I hadn’t yet realized that rumors were circulating Reddit and other anti-vaxxer platforms, claiming that infertility and miscarriage are unreported side effects of the vaccines.

The key word there, of course, is “rumors.” Quite like much of the persistent and problematic discourse regarding vaccines, these claims of vaccines leading to fertility issues are completely false and unfounded.

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Still, fictional gossip can be convincing, as proven by the panicked texts from my friend, as well as a recent Mira Fertility study: 68 percent of Mira’s customers still feel hesitancy towards the vaccines, suspecting it “causes fertility issues.” It’s worth noting, however, that only 20 percent of those surveyed actually consulted with a doctor or OBGYN regarding vaccination, so it’s unclear where this apprehension initially came from.

The fact of the matter is: The science shows that the vaccine is safe and effective — and does not affect fertility. But if you’re still concerned, we queried several reproductive health experts about this very subject to help assuage any fears you may have.

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“There is absolutely no clinical evidence or proven theory as to how vaccines would cause infertility,” says Dr. Kelly Culwell, M.D., a fellowship trained OB/GYN who previously worked with the World Health Organization and Planned Parenthood. “All major women’s health professional organizations — including the American Society for Reproductive Medicine [(ASRM)], a group which includes infertility experts — agree that there is no evidence to support this concern.”

It’s true: ASRM specifically affirms, “COVID-19 vaccination is recommended for women who are contemplating pregnancy or who are pregnant in order to minimize risks to themselves and their pregnancy,” adding that this guidance is consistent with that of the Advisory Committee for Immunization Practices of the U.S. Center for Disease Control and Prevention and the American College of Obstetricians and Gynecologists.

And such is the case for all vaccines, not just those that help prevent Covid.

“There is no comparable case where a vaccine has caused infertility or miscarriage,” says Dr. Amy Roskin, M.D., board-certified OB/GYN and medical director of The Pill Club. “In general, vaccines protect against diseases and illnesses that pose greater risks to pregnant women.”

If you’re concerned by the fact that technically, fertility was not specifically studied in the COVID vaccine clinical trials, Dr. Cary L. Dicken, M.D., F.A.C.O.G., a reproductive endocrinologist and infertility specialist at RMA Long Island IVF, has some insight. “No loss of fertility has been reported among trial participants or among the millions who have received the vaccines to date,” she explains. “In addition, no signs of infertility appeared in animal studies. Based on the mechanism of action of the vaccine, loss of fertility is unlikely.”

Plus, many pregnant people in the U.S. have received the vaccines, and their pregnancies remain unaffected. “Data collected have not predicted any safety concerns for pregnant individuals,” she continues. “Pregnancy and neonatal outcomes for 827 completed pregnancies was reported in the New England Journal of Medicine and [there was] no increased risk for miscarriage, [or] pregnancy complication.”

What’s more, the ability to get pregnant, and/or suddenly losing a pregnancy, doesn’t really work like that. It’s not something that someone can cause in regular, everyday life — unless by the one thing for which there is no antidote: Time.

“Age is the greatest reason for infertility,” Dr. Taraneh Shirazian, M.D., board certified gynecologist, director of Global Women’s Health at NYU’s College of Global Public Health and founder of Mommy Matters, says. Otherwise, there are technically some conditions that may affect someone’s ability to ovulate, like polycystic ovarian syndrome, thyroid disorders, uterine polyps, endometriosis, primary ovarian insufficiency (early on-set menopause), and certain forms of cancer. The Mayo Clinic also cites tobacco and alcohol use as possible factors, though fertility is far more complicated than a list of potential risk factors and truly depends on the individual — and not whether or not they’ve been vaccinated.

“There is no evidence and also no biologic plausibility that vaccines would impact fertility…[or] your reproductive organs,” Shirazian maintains. “Even if you have spotted on the cycle where you receive the vaccine, that is considered a common response to external stress.”

Understanding those menstrual cycle side effects

So the numbers reported out of the United Kingdom (with 30,000 menstruating people reporting changes to their cycles) and anecdotal reports of shifts in cycles are not cause for alarm. In fact, it’s to be expected, in a way: Anything that impacts the immune system, ranging from new medication from a vaccine to stress, can potentially trigger this side effect. And while experts have said these side effects are short-lived and harmless, when it comes to studying the vaccines on people who get periods they do want to see more data to understand the why behind them.

“There is a large amount of scientific evidence showing that [the] hormonal system is very delicate and can be influenced easily by physical, chemical, and emotional stressors,” Dr. Mindy Pelz, M.D., a functional medicine and women’s health expert and author of The Menopause Reset, explains. “This vaccine could fall into the category of a stressor that has an impact on the ebbs and flows of hormones.”

“Any stress to the body or immune system can potentially cause a temporary delay or change to menstruation,” Culwell concurs. “It is possible that this could happen with other vaccines as well, [but] is a very unusual time where we have large numbers of people getting vaccinated at the same time so that may explain why we are hearing a cluster of these reports.”

“There is some evidence that a strong immune response can impact your period,” adds Roskin. “Cells from the immune system are involved in the regulation, build up and shedding of the endometrial lining that causes menstrual bleeding.”

As for the rumors regarding pregnancy loss: I asked about those, too.

“Miscarriages are unfortunately very common — half of all pregnancies end in miscarriage — but most people aren’t aware of this,” says Culwell. “So the fact that some women have had miscarriages around the time they received a COVID vaccine leads people to the wrong conclusions when really it is just a bad coincidence.”

“The ‘theory’ behind why this would be true — that a protein that the vaccine recognizes is similar to a protein required for a pregnancy to establish — has been completely debunked,” she adds.

“The only thing the vaccine can do regarding reproduction is protect you against the very serious complications that can arise due to COVID in pregnancy.”

Every expert — and major reproductive health organization — I spoke with advised individuals who are pregnant and/or hoping to conceive to receive the vaccine. That went for all genders, regardless of whether or not they’re the one carrying out the pregnancy. In fact, the Society for Male Reproduction (SMRU) and the Society for the Study of Male Reproduction (SSMR) have specifically recommended that the vaccine not be withheld from men hoping to conceive, according to Dicken.

“COVID in pregnancy has been shown — through evidence — to cause severe disease and increase complications. Pregnant women are at risk for more severe disease, ICU stay, hospitalization than non-pregnant women their age [and] should get the vaccine,” says Shirazia. “An added bonus is that mom’s antibodies will also cross to the fetus and protect the newborn.”

“There is sound data that suggests that pregnancy is a high-risk factor for developing severe illness,” Dicken affirms. “There is presently no data of any adverse effects of the vaccine on an individual’s fertility. I feel the benefit of vaccination outweighs any unknown risk.”

“I agree with all of the professional medical organizations on this one,” Culwell concludes. “The only thing the vaccine can do regarding reproduction is protect you against the very serious complications that can arise due to COVID in pregnancy.”

A version of this story was published May 2021.

Before you go, check out some of the different period products on the market right now:

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