7 Studies that Evince COVID-19 Vaccines Negatively Affect Women’s Menstrual Cycles

Here is a list of 7 studies that show ample evidence of the mRNA and DNA COVID-19 “vaccines” negatively affecting women’s menstrual cycles.

This list also includes a look at how a single study ultimately funded by the NIH and Bill and Melinda Gates—showing relatively minor effects of the injections on menstrual cycles—was able to capture all the attention away from the issue.

Women from the world over have reported irregularities in their menstrual cycles following the administration of an mRNA or DNA COVID-19 “vaccine.” The proportion of “vaccinated” women experiencing these often “disturbing” disruptions to their menstrual cycles appears to be large; estimated by different studies at between 20% and nearly 50%. (And in some particular categories, significantly higher than that.) The menstruation disruptions often present as heavy bleeding, but the issue can grow dire.

Thrombocytopenia, or having abnormally low levels of platelets—a.k.a. thrombocytes—in the blood, is a well-documented side effect of the COVID-19 “vaccines”; with VAERS hosting 5,350 reports as of this writing. The condition frequently appears concurrently with the menstrual cycle disruptions and may, in some number of cases, cause them.

Dr. Lee Merritt, who completed an Orthopedic Surgery Residency in the U.S. Navy and served for nine years as a Navy physician and surgeon, highlights the frightening number of menstrual issues—as well as other hematological issues—people have suffered from thanks to the COVID-19 “vaccines” in a succinct letter in the Journal of American Physicians and Surgeons. Merritt, who is a member of America’s Frontline Doctors (AFLDS), has not only been keeping abreast of the latest COVID-19 “vaccine” literature, but has also been tending personally to those injured by the injections.

Merritt notes that she searched the VAERS database for words associated with bleeding problems; such as “platelets,” “bleeding,” “hemorrhage,” or “thrombocytopenia,” and found 370 adverse events including the search terms. The chart below from Merritt’s letter shows the breakdown of the events, including “28 cases of vaginal bleeding in non-pregnant women, seven [of which]…were often accompanied by systemic symptoms—dizziness, blurred vision, lymph node swelling, [and] welts.”

In May of 2021, Merritt wrote in an update that she attempted to revise her report with the latest VAERS numbers from May; Merritt had used VAERS reports from December, 2020 to March, 2021 for her analysis. She, however, decided not to update the letter, as when she went back and searched VAERS “in identical fashion,” 6,290 entries were retrieved, including 291 deaths.

Dr. Lee Merritt / Journal of American Physicians and Surgeons

Below is a list of seven studies offering a glimpse into how the COVID-19 “vaccines” affect women’s menstrual cycles. The studies support Dr. Merritt’s concerns, even if many of their authors downplay the significance of the overall body of research and pharmacovigilance data.

1. Preprint on SSRN (Posted January 14, 2022)

TITLE: Increased Occurrence of Menstrual Disturbances in 18- to 30-Year-Old Women after COVID-19 Vaccination

In this study scientists from the Norwegian Institute of Public Health used mobile-phone questionnaires to collect reports of menstrual disturbances from 5,688 women aged (18-30 years). The scientists note they “estimated the relative risk of menstrual disturbances according to vaccination in a self-controlled case-series design, using the first six weeks after vaccination as the exposed period.”

The authors write in their conclusion that: We found a significant increase in menstrual disturbances after vaccination, particularly for heavier bleeding than usual, longer duration and for short interval between menstruations. The authors also say that the “Mechanisms underlying these findings may involve bleeding disturbances in general, as well as endocrine alterations.

The study notes that “The risk of heavy bleeding after the second dose, given that it had occurred after the first, was 65.7%,” and that they “observed increased risks after vaccination also for other menstrual disturbances.


2. Preprint on MedRxiv (Posted December 6, 2021)

TITLE: COVID-19 vaccination and menstrual cycle changes: A United Kingdom (UK) retrospective case-control study

In this study a team of researchers led by Alexandra Alvergne and Gabriella Kountourides, both of whom are at the School of Anthropology and Museum Ethnography at the University of Oxford, “performed a secondary analysis of a retrospective online survey titled ‘The Covid-19 Pandemic and Women’s Reproductive Health,’ conducted in March 2021 in the UK before widespread media attention regarding potential impacts of SARS-CoV-2 vaccination on menstruation.”

The authors note participants for the online study “were recruited via a Facebook ad campaign in the UK and eligibility criteria for survey completion were age greater than 18 years, having ever menstruated and currently living in the UK.” In total, 26,710 people completed the survey. For their analysis, Alvergne and Kountourides et al. selected 4,989 participants who were pre-menopausal and vaccinated.

The authors say that written accounts from participants report diverse symptoms; the most common words being “cramps”, “late”, “early”, “spotting”, “heavy” and “irregular”; with a low level of clustering among them.

In their conclusion, the authors say that: “Following vaccination for COVID-19, menstrual disturbance occurred in 20% of individuals in a UK sample. Out of 33 variables investigated, smoking and a previous history of SARS-CoV-2 infection were found to be risk factors while using oestradiol-containing contraceptives was found to be a protective factor. Diverse experiences were reported, from menstrual bleeding cessation to heavy menstrual bleeding.”


3. Frontiers in Medicine (Posted October 8, 2021)

TITLE: BNT162b2 and ChAdOx1 SARS-CoV-2 Post-vaccination Side-Effects Among Saudi Vaccinees

A team of researchers at the College of Medicine at Taif University in Taif, Saudi Arabia distributed an online questionnaire that was “designed to screen the local, systemic, and allergic post vaccination reactions for vaccinees who received either one or two doses of the BNT162b2 [Pfizer-BioNTech] vaccine or one dose of the ChAdOx1 [AstraZeneca] vaccine.” The authors report that 4,170 individuals reported their responses: with 2,601 receiving one dose of Pfizer-BioNTech—of whom 456 completed the second dose—and 1,569 receiving a single dose of AstraZeneca.

The researchers conclude, in part, that: The vaccines’ side effects were reported in 85.6% of Pfizer-BioNTech vaccinees and 96.05% of AstraZeneca vaccinees. The researchers also conclude that: “Abnormal menstrual cycle (delaying/increase hemorrhages or pain) was also reported in 0.98% (18/1846) of Pfizer-BioNTech and 0.68% (7/1028) of [AstraZeneca] vaccinees, while deep vein thrombosis was only reported in a single case vaccinated with BNT162b2 vaccine.” On top of that, “Menstrual disturbance, including excessive hemorrhage and irregular menstrual cycle were reported after the administration of [Pfizer-BioNTech] (643 cases) and [AstraZeneca] (315 cases).”

The researchers speculate that “Thrombocytopenia and underlying platelets disorders, or possible hormonal disturbance may explain excessive menstrual bleeding. The study also notes that Women are more prone to developing more severe side effects and for longer durations.”


4. PNAS Front Matter (Posted as preprint October 2021)

TITLE: Characterizing menstrual bleeding changes occurring after SARS-CoV-2 vaccination

In this study a team of researchers at the University of Illinois at Urbana-Champaign, led by PhD researcher Katharine MN Lee, established “an emergent, exploratory, mixed methods survey instrument intended to capture a wide range of responses from current and formerly menstruating adults.” The researchers were able to survey 39,129 women; focusing specifically on data related to menstrual bleeding in “people who menstruate regularly” or breakthrough bleeding “in people who do not currently menstruate.”

The researchers conclude that: “The menstrual changes in the full group of pre-menopausal regularly menstruating people (N=21,380) included period flow change and period length change. The highest proportion of respondents reported noticing changes to their reported period symptoms 14 or more days after receiving their vaccines (Dose 1: 29.94%; Dose 2: 26.85%).

The researchers note that “Due to the proportion of people experiencing heavy flow after at least one of the vaccines, we grouped regularly cycling individuals with any heavier flow into one condition (“heavier”; N=7,429 of 17,642; 42.11%), people who experienced no change in flow after either dose into the second condition (“no change”; N=7,684; 43.56%), and the remainder of people who experienced a combination of lighter and no change after their doses into a smaller third condition (“not heavier”, N=2,529; 14.34%). In total, 727 were missing dose 1 period flow information and 3,031 were missing dose 2 period flow information. We similarly grouped people reporting any longer bleeding into one condition (“longer”; N=5,9780 of 17,366; 34.42%), people who experienced no change in period length after either dose into a second group (“no change”, N=8,914; 51.33%), and the remainder of people who experienced a combination of shorter and no change to period length across doses into a smaller group (“not longer”, N=2,474; 14.25%).

The study’s authors also note that “menstruation is seldom considered a variable during vaccine trials aside from determining last menstrual period as part of established protections against volunteers being or getting pregnant. In the case of the COVID-19 injections, however, “Data mining and signal detection in VAERS has resulted in the identification of several possible effects on menstruation that suggest further research is needed.”


5. Obstetrics & Gynecology (Posted January 5, 2022)

TITLE: Association Between Menstrual Cycle Length and Coronavirus Disease 2019 (COVID-19) Vaccination

This study published in Obstetrics and Gynecology was led by Dr. Alison Edelman, a professor of obstetrics and gynecology with specialty training in family planning, public health, and research at Oregon Health & Science University (OHSU) in Portland, Oregon. (Edelman discloses that she receives honoraria and travel reimbursement from the WHO and several other organizations. Edelman is also a principal investigator for OSHU, which receives funding from Merck, the Bill and Melinda Gates Foundation, and the NIH, amongst others.)

Edelman et al.’s study begins by noting that “Concerns about a possible association between coronavirus disease 2019 (COVID-19) vaccination and abnormal menstrual cycles may lead to vaccine hesitancy.” The authors note that “Unfortunately, clinical trials of the current COVID-19 vaccines did not collect menstrual cycle outcomes postvaccine [and] VAERS (Vaccine Adverse Event Reporting System) does not actively collect information regarding menstrual cycles, and, by May 2021, only a small number of individuals (fewer than 200) had self-reported a menstrual-related issue to VAERS.” The authors do add, however, that “Social media reports suggest menstrual disturbances are much more common but that these disturbances appear to be temporary.”

To “directly [address] concerns raised by self-reports through VAERS and public discourse,” Edelman et al. analyzed prospectively tracked menstrual cycle data using the phone application “Natural Cycles.” 

The authors report they “included U.S. residents aged 18–45 years with normal cycle lengths (24–38 days) for three consecutive cycles before the first vaccine dose followed by vaccine-dose cycles (cycles 4–6) or, if unvaccinated, six cycles over a similar time period [and] calculated the mean within-individual change in cycle and menses length (three prevaccine cycles vs first- and second-dose cycles in the vaccinated cohort, and the first three cycles vs cycles four and five in the unvaccinated cohort).” In all, the researchers included 3,959 Natural Cycles respondents; including 2,403 women who were vaccinated and 1,556 who weren’t.

In conclusion, the authors say that: “We evaluated 23,754 menstrual cycles prospectively reported by 3,959 U.S. individuals to evaluate whether COVID-19 vaccination is associated with menstrual cycle disturbances during cycles when vaccination occurs. After adjusting for confounders, we found that normally cycling individuals experienced small variations in cycle length regardless of vaccination status. Statistically significant differences existed between vaccination status groups, but the change in cycle length was less than 1 day, which is below the reportable difference in the menstrual cycle tracking application and is not clinically significant.” The authors also note that their “results cannot be explained by generalized pandemic stress because [their] unvaccinated control group saw no changes over a similar time period.”

NOTE: Along with OSHU’s funding coming from, in part, the NIH and the Bill and Melinda Gates Foundation, study co-author Leo Han also serves as an OSHU principal investigator who receives funding from the NIH. The other authors on the study work for Natural Cycles.


6. Open Journal of Obstetrics and Gynecology (Posted November 2021)

TITLE: Possible Effect of COVID-19 Vaccines on Menstruation in Cape Coast, Ghana, West Africa: Case Series Report

In this study a team of physician-researchers from the School of Medical Sciences at the University of Cape Coast in Ghana reported three “cases of abnormal uterine bleeding which seems to be linked to Covid-19 vaccines.” The three reports include “two incidents of heavy menstrual bleeding and one incident of inter-menstrual bleeding which are likely associated with COVID 19 vaccination, even though the causality could not be confirmed.”

The physician-researchers describe three case reports amongst women ages 41, 33, and 34. The women have varying health histories and underlying conditions. Amongst their reported symptoms were lengthened menses, and even “small clots” of blood. One of the women reported a prolonged menses that lasted for more than 30 days.

In conclusion, the authors say that there “are emerging possible new side effects such as abnormal uterine bleeding post Covid-19 vaccination” and that in this paper they’re reporting three such cases “in a context of abnormal menstruation, which symptoms seem to be linked to Covid-19 vaccines.” The authors say they report these “cases because there is no available data in literature on post Covid-19 vaccines menstrual abnormalities reported in black population and particularly in Sub Saharan Africa.”


7. Journal of Cellular and Molecular Medicine (Posted December 29, 2021)

TITLE: Cardiovascular and haematological events post COVID-19 vaccination: A systematic review

This study, funded by the Qatar National Library,  reviewed “all published data about the [cardiovascular] and haematological complications which have been reported post COVID-19 vaccination in an attempt to reflect the true picture about the occurrence of such rare events.” The authors screened 16,940 studies, but ultimately excluded all but 99 of them.

Amongst the 99 studies the authors note that “A total of 158 CV [“cardiovascular”] and haematological events were reported in 122 individuals who received the Pfizer vaccine (50 CI, 45 thrombosis, 43 TP, nine hemorrhage and 11 others including eight stage 2 hypertension (HTN) and three microangiopathy). A total of 45 CV and haematological events were experienced following receiving the Moderna vaccine (25 CI and 17 TP [“thrombocytopenia”] without thrombosis, one haemorrhage and two others including one stage 2 HTN and one hypertensive crisis). Two hundred and seventeen individuals who received AstraZeneca vaccine experienced 747 CV and haematological events as some of them suffered from multiple events (74 cardiac problems, 375 thrombosis, 206 TP and 92 haemorrhage). Sixty-one events were experienced by 21 individuals who received the J&J vaccine (one cardiac, 40 thrombosis and 20 TP). A total of two cases experienced CV and haematological events following receiving the CoronaVac vaccine (one Kounis Syndrome, Type I variant and 1 haemophagocytic lymphohistiocytosis).”

The authors note that “Among Pfizer, three were ICH, two hematuria, one vaginal bleeding and one GI bleed. The case after Moderna was that of vaginal bleeding. Among AstraZeneca, 40 were ICH, two GI bleeds, two adrenal haemorrhage and three unspecified bleeding. As for J&J, eight were ICH [“intracranial haemorrhage”] only and one had both ICH and mild retroperitoneal, intraperitoneal and pelvic haemorrhage. Smadja et al. reported 32 cases of thrombocytopenia associated to the venous and arterial thrombotic events after Pfizer vaccination while only eight and 14 cases were reported post Moderna and AstraZeneca vaccination.”

The authors also highlight a difference in adverse event rate amongst men and women. The authors write that:

It was observed that in some of the included studies, females represented more than 50% of the total affected cases. For example, Tobaiqy et al. reported that more female patients experienced thrombotic events at twice the rate that male patients did (n=19 women, n=9 men) which could be attributed to well-established hormonal factors. It is well-known that oral contraceptives increase the risk of thromboembolism in women of childbearing age. It has since been hypothesized that estrogen itself has prothrombotic effects although the exact mechanism has not been fully elucidated. Studies have shown that in the general population, when stratified by age, women generally have increased risk of thrombosis as compared to men of the same age, given their higher levels of estrogen. However, when the studies were compiled, there was no specific pattern for one gender being affected more than the other.”

The researchers also found that a “total of 460 thrombotic events were reported post COVID-19 vaccination of which 9.8% were after Pfizer, 81.5% after AstraZeneca and 8.7% after J&J vaccination.”



Along with the seven studies above, two letters in The British Medical Journal help to highlight the scale of the problem with COVID-19 “vaccines” and menstrual cycle disruption. The first is from lecturer in reproductive immunology Victoria Male, who writes in a letter titled “A link is plausible and should be investigated,” that:

“Common side effects of covid-19 vaccination listed by the UK’s Medicines and Healthcare Products Regulatory Agency (MHRA) include a sore arm, fever, fatigue, and myalgia. Changes to periods and unexpected vaginal bleeding are not listed, but primary care clinicians and those working in reproductive health are increasingly approached by people who have experienced these events shortly after vaccination. More than 30,000 reports of these events had been made to MHRA’s yellow card surveillance scheme for adverse drug reactions by 2 September 2021, across all covid-19 vaccines currently offered.

Male goes on to say that:

“Although reported changes to the menstrual cycle after vaccination are short lived, robust research into this possible adverse reaction remains critical to the overall success of the vaccination programme. Vaccine hesitancy among young women is largely driven by false claims that covid-19 vaccines could harm their chances of future pregnancy. Failing to thoroughly investigate reports of menstrual changes after vaccination is likely to fuel these fears. If a link between vaccination and menstrual changes is confirmed, this information will allow people to plan for potentially altered cycles. Clear and trusted information is particularly important for those who rely on being able to predict their menstrual cycles to either achieve or avoid pregnancy.”

While Male clearly seems to believe the benefits of the “vaccines” outweigh the risks, she’s at least still highlighting “a link between vaccination and menstrual changes,” which is unequivocally there.


In a letter titled “CoViD-19 post-vaccine menorrhagia, metrorrhagia or postmenopausal bleeding and potential risk of vaccine-induced thrombocytopenia in women,” author Hamid Merchant, a Subject Leader in Pharmacy at the University of Huddersfield in the U.K., says that:

Many women across the world after receiving CoViD vaccines are complaining of irregularities in their menstrual bleeding; some experiencing heavy menstrual bleeding (menorrhagia), some bleeding before their periods were due or bleeding frequently (metrorrhagia/polymenorrhea), whereas some are complaining of postmenopausal bleeding.

As of 5th April 2021, there have been ~958 cases of post-vaccination menstrual irregularities, including vaginal haemorrhages, that were recorded in MHRA’s adverse event reports. There were twice more cases of menstrual irregularities with CoViD Vaccine AstraZeneca than Pfizer (643 vs 315 respectively). It is anticipated that the actual numbers of cases are much higher than the numbers recorded in the pharmacovigilance systems as many women in different cultural context may have felt uncomfortable to talk about it, may not have thought that it was vaccine-related, or may have not been encouraged by their clinicians to make an official report into the adverse events reporting system.”

Critically, Merchant says that:

The ‘heavy menstrual bleeding’ has been previously reported in females with underlying platelets disorders. It is plausible that the vaccine-induced thrombocytopenia may be an explanation for the recent incidences of heavy menstrual bleeding experienced by women in different countries after the CoViD-19 vaccination. The significant loss of blood in many women may lead to severe anaemia, further exacerbate thrombocytopenia, and therefore may significantly increase the risk of haemorrhages and clots.

Merchant adds:

Clinicians and front-line healthcare workers are advised to encourage women to report heavy menstrual bleeding or other extraordinary bleeding events post-vaccination formally into the vaccine adverse events reporting system and seek prompt medical advice. Public health agencies and regulatory authorities are also requested to investigate these incidences and issue further warnings, as this can, possibly be an early sign of potentially fatal vaccine-induced prothrombotic thrombocytopenia leading to rare CVST events in younger women. There may be some women with pre-existing conditions or those on certain medications that may be at increased risk of experiencing post-vaccination severe adverse events and early warnings will help saving lives.”



Incredibly, although expectedly, just one of the seven studies above populates the entire front page of any Google search related to the effects of the COVID-19 “vaccines” on a woman’s menstrual cycle: Edelman et al.’s study in Obstetrics & Gynecology. The study ultimately funded by the NIH and the Bill and Melinda Gates Foundation. The study that shows the smallest amount of impact from the COVID-19 “vaccines” on the menstrual cycle, and focuses only on cycle length, rather than critical issues like heavier-than-normal bleeding and blood clots. (Many of the top results on the Brave and DuckDuckGo search engines refer to Edelman’s study as well.)

Although it’s obviously impossible to say why this is the case, having Edelman’s study out there—ranked at the top of Google’s search results and blasted in media articles like this one on NPR (“COVID vaccines may briefly change your menstrual cycle, but you should still get one”) and this one in The Los Angeles Times (“Periods and COVID-19: Do vaccines affect menstrual cycles?”)—means that the general public only receives the message: Yes, there’s a problem, but it’s certainly only minor.

As of this writing there are 5,760 VAERS reports containing the phrase “menstrual cycle.” (According to a 2011 study performed by Harvard Pilgrim Health Care, Inc., there may be an underreporting factor of up to 100 for VAERS.) Below is a minuscule glimpse at the summaries for some of the reports. Note they contain phrases like “issue with menstrual cycles [and] Being late and an ungodly amount of blood, clots, and cramps….” and “heavy vaginal bleeding that lasted 10 days.”


In a report in The New York Times from February of 2021, the paper reported that “vaccine recipient, Sarah C., 48, a teacher in Arlington, Tex., received the Moderna vaccine on Jan. 3…[and] Two weeks later, she began to have heavy vaginal bleeding.” Her obstetrician ordered blood work on her, and subsequently urged her to go straight to the emergency room as her blood count showed zero platelets. The results were confirmed at the hospital and the teacher spent four days receiving platelet transfusions, immune globulins, and steroids.

The Times ends its report by quoting Sarah C. who said she was still “all for the vaccine [even though she] had a terrible horrible reaction.” The Times reported that Sarah’s doctors still encouraged her to get a second dose.


Edelman et al.’s study in Obstetrics & Gynecology has now been pulled. It’s unclear why.

Feature image: Marco Verch Professional Photographer

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