The European Medicines Agency’s drug safety committee announced it will probe thousands of reports of women suffering menstrual changes after getting Covid vaccines made by Pfizer or Moderna.
The EMA is investigating cases of heavy bleeding and missed periods following vaccination.
It will look through all the reported incidents in the EU and clinical trial data, as well as review the scientific literature.
The EMA’s panel previously investigated the connection between irregular periods and Covid vaccines but said they could not establish a firm link. It is reopening the case after receiving ‘spontaneous reports of menstrual disorders’ more recently.
Women around the world have reported an irregular period after getting the mRNA vaccines, with some studies suggesting the issue affects four in 10 women.
More than 50,000 reports of period changes, including late periods, have been logged in the UK alone, finally triggering a review by the Medicines and Healthcare Products Regulatory Agency (MHRA).
The EMA’s Pharmacovigilance Risk Assessment Committee (PRAC), which oversees the safety of medicines, is carrying out the assessment.
It will review all available evidence on mRNA vaccines and period changes among women, including reports from vaccinated women, clinical trials and studies.
They will be looking into whether the vaccine triggered heavy periods — bleeding that affects a person’s quality of life — or temporarily stopped periods — medically known as amenorrhea when a woman does not have a period for three months or more.
The UK’s MHRA is already investigating reports of period problems, as well as unexpected vaginal bleeding, post-vaccination.
Two MHRA sub-committees — the Vaccines Benefit-Risk Expert Working Group and the Medicines for Women’s Health Expert Advisory Group — are also investigating the evidence around the claims.
Up to February 2, the watchdog had received 50,060 reports of menstrual disorders after getting a Covid jab.
Nearly 72million Covid vaccines had been given to women by then.
A study of more than 4,000 women in the US found periods lasted 15 hours longer in women who had a first dose and 19 hours longer among double-jabbed.
The Oregon Health and Science University scientists leading the study said the changes were ‘small’ and ‘temporary’.
The length of the menstrual cycle varies between individual women, but the average is every 28 days.
However, cycles as short as 21 days or as long as 40 are not considered unusual.
The NHS advises women to contact their GP if their periods are irregular in certain situations.
These include: if their periods suddenly become irregular and they are under 45-years-of-age, their periods come more often than every 21 days and less often than every 35 days, their period lasts longer than seven days, and there is a difference of at least 20 days between the shortest and longest menstrual cycle.
Irregular periods can also lead to problems when women are trying to get pregnant as it becomes difficult to accurately track ovulation, the time when they are most likely to conceive.
Like other vaccines and medicines, clinical trials of the Covid jabs did not include pregnant women.
This meant the UK’s vaccine advisers, the Joint Committee on Vaccination and Immunisation (JCVI), did not have enough evidence to recommend pregnant women should get vaccinated when jabs were initially rolled out last winter.
But real-world data from the US — where 90,000 pregnant were given doses of Pfizer or Moderna — did not reveal any safety concerns.
So the JCVI advised that these jabs should be offered in the UK.