Thursday 16 September 2021 3:49 pm

Covid-19: Changes to menstruation after vaccination should be investigated, BMJ report urges

More than 30,000 women after their vaccinations have reported changes in their menstrual cycle to the UK’s medicines watchdog, which a British Medical Journal report published today has urged to be investigated.  

Common temporary side effects of the Covid-19 vaccines listed by the Medicines and Healthcare Products Regulatory Agency (MHRA) include a fever, fatigue and muscle pain – but menstrual changes are not listed, despite the increasing number of reports.

The reports, filed through the MHRA’s yellow card side effects reporting scheme until 2 September, have been pushing vaccine hesitancy among young women who fear it may impact their future chances of pregnancy, the report said.

Imperial College London’s Victoria Male, author of the report, cautioned that while there is no evidence of the MHRA-approved vaccines having negative impacts on fertility, menstrual changes should be investigated to encourage vaccine uptake.

“Most people who report a change to their period after vaccination find that it returns to normal the following cycle and, importantly, there is no evidence that Covid-19 vaccination adversely affects fertility,” Male wrote.

“Vaccine hesitancy among young women is largely driven by false claims that Covid-19 vaccines could harm their chances of future pregnancy,” she added. “Failing to thoroughly investigate reports of menstrual changes after vaccination is likely to fuel these fears.”

The MHRA has stated that the evaluation of its yellow card reports does not support a link between changes to menstrual periods and Covid-19 vaccines, due to the number of reports being relatively low in comparison to both the number of people vaccinated and how common menstrual disorders are.

However, Male, a lecturer in reproductive immunology, said that the way in which yellow card data is collected, makes firm conclusions difficult and 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.”