Women’s periods may be slightly late after COVID vaccine: study


WASHINGTON, United States (AFP)— Women vaccinated against COVID-19 saw a slight delay in their period of almost a day compared to those who were unvaccinated, a US government-funded study said Thursday.

But the number of days of bleeding was not affected, according to the research carried out on nearly 4,000 individuals and published in “Obstetrics & Gynecology.”

Lead author Alison Edelman of the Oregon Health & Science University told AFP the effects are small and expected to be temporary, a finding that is “very reassuring” as well as validating for those who experienced changes.

The study can also help counter anti-vaccine misinformation on the topic, which is rampant on social media.

The slight increase in menstrual cycle length is not clinically significant. Any change of fewer than eight days is classified as normal by the International Federation of Gynecology and Obstetrics.

Period cycles generally last about 28 days, but the precise amount varies from one woman to another, as well as within an individual’s lifetime. It can also change during times of stress.

For their study, the scientists analysed anonymised data from a fertility tracking app, among women aged 18 to 45 who were not using hormonal contraception.

Some 2,400 participants were vaccinated — the majority with Pfizer (55 per cent), followed by Moderna (35 per cent) and Johnson & Johnson (seven per cent).

About 1,500 unvaccinated women were also included as a comparison.

Among the vaccinated group, data was collected from three consecutive cycles before vaccination and from three more consecutive cycles, including the cycle or cycles in which vaccination took place.

For unvaccinated individuals, data was collected for six consecutive cycles.

– Immune response to vaccine –

On average, the first vaccine dose was associated with a 0.64-day increase in cycle length and the second dose with a 0.79-day increase, when comparing the vaccinated to unvaccinated group.

The immune system’s response to the vaccine could be behind the change.

“We know that the immune system and the reproductive system are interlinked,” said Edelman.

A revved-up immune system might have an impact on the hypothalamic-pituitary-ovarian axis — what Edelman calls the “highway of how your brain talks to your ovaries, talks to your uterus,” or simply the “body clock.”

Specifically, the production of inflammatory proteins called cytokines appears to disrupt the way this axis regulates the timing of menstrual cycles.

The changes seem most pronounced when vaccination takes place early in the follicular phase, which starts on the first day of the menstrual period (bleeding) and ends when ovulation begins.

In fact, a subgroup of people who received two injections of the Pfizer or Moderna vaccines during the same cycle, as opposed to two different cycles, saw an average increase in cycle length of two days — but the effect again appears temporary.

The team now hopes to gather more data on subsequent cycles among vaccinated women to confirm a long-term return to baseline, and expand the study globally so they can differentiate the effects between vaccine brands.

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  1. Hmmmm… Someone is gonna pay for this damage. We all know that is a big effect on women rightdue to this thing . I heard of a friend who is now saying she’s having issues, not good. Now the government who followed the beast needs to come clean with their country and tell us the TRUTH. Men and women are having suck big effects with this nonsense and that man the flawed clown who created this thing will pay a very big price for distroying lives . But woe woe woe unto them. People we must REPENT EVERY SINGLE DAY, the spiritual warefare is so heavy in so many people.

  2. Yes, Ladies you’re not crazy. It’s supposed to mess with your reproductive system, and no this is not the same equipment you need to have healthy babies…I think…

  3. I heard from a friend that his cousin’s friend said bill gates had put microchips in the vaccine which track us but also prevent pregnancy because bill gates wants everyone to die. I believe this despite 99% of the world’s scientists saying otherwise.

    • Carn even sue for a likkle change if subbon happen to you. Trust us they say…do it for the good of society…i could end up concluding the vaccine is safe but I will NEVER trust you. Never!…..Ever….

  4. Surgeon Destroys Mask Myth:

    Since the beginning of the pandemic I’ve read hundreds of studies on the science of medical masks. Based on extensive review and analysis, there is no question in my mind that healthy people should not be wearing surgical or cloth masks. Nor should we be recommending universal masking of all members of the population. That recommendation is not supported by the highest level of scientific evidence.

  5. Dr. Richard Bartlett who has been a frontline warrior fighting medical tyranny and championing safe and effective treatments to the irrational fear of Covid. He has practiced medicine in Texas for 28 years, served on former Governor Perry’s healthcare task force, and is a medical expert for a CBS affiliate in west Texas. Lets all kill the spirit of fear and stand tall and united.


  6. Alison Edelman is a professor of Obstetrics and Gynaecology, the Fellowship Director of complex family planning at Oregon Health & Science University (OHSU). She completed all of her medical training at OHSU and was the first OHSU family planning fellow in 2001.

    Dr Edelman is also an active clinician-scientist with independent research funding and is an Oregon site CO-I for the National Institutes of Health (NIH) contraceptive clinical trials network.


    However, what Dr Edelman (and this ANR article) INTENTIONALLY forgets to mention, is that the NIH and the BILL GATES Foundation together provides more than half of all global health research funding.

    And this in itself is why people are arguing for a more UNBIASED AND BALANCED DEBATES/CONVERSATIONS ON THE PROBLEMS OF THE VACCINES.

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