After Covid jab, period changes are seen to be short-lived

Dr. Victoria Male of Imperial College London described research of women's cycles in the United States and Norway "reassuring."

She also blamed disinformation for fueling infertility fears.

There is no proof that Covid vaccinations impact the capacity to bear children, according to the UK regulator.

More than 37,000 reports of unexpected vaginal bleeding, heavier and delayed periods following a Covid shot have been received by the Medicines and Healthcare Products Regulatory Agency.

It has long maintained that there is no proof of a link between the vaccine and the women's periods, but scientists have asked for greater investigation.

A study of nearly 4,000 women in the United States who used a menstrual-cycle tracking app discovered that their next period was delayed by half a day after the second vaccine dosage, but not after the first.

Complaints commonly encountered

There was a two-day delay in those who had two doses in the same cycle, but Dr Male said this was unlikely in the UK, where the time between doses is at least eight weeks.

One in ten of the women's cycles lengthened by more than eight days, compared to one in twenty-five unvaccinated women, although their periods recovered to normal after just two cycles.

Another research of more than 5,600 people in Norway demonstrates how much spontaneous variation in periods can occur.

"Changes to the menstrual cycle do occur following immunisation," Dr. Male stated, "but they are modest in comparison to natural fluctuation and soon reverse."

She explained that women's concerns stemmed from "misinformation that Covid-19 vaccinations induce female infertility."

More research into pregnancy rates in couples trying to conceive is needed to prove they don't.

A Covid infection, on the other hand, "may lower sperm count and quality," and knowing more about this would allow doctors to give patients the best counsel possible.

A study of UK users of the same menstrual-cycle-tracking app is scheduled to be released soon.

Dr Male noted that the "poor priority" of menstruation and reproductive health meant it had taken a long time to get to this stage.

Even before getting vaccinated, nearly 40% of people noticed at least one alteration, with the most common complaint being heavier than typical bleeding.

In the United Kingdom, almost 51 million doses of Covid vaccination were provided to women.