Trigger effect
New Zealand Listener|January 14-20 2023
The Covid vaccine can cause short-term changes in period timing and heaviness, but this is probably just the immune system doing its job, researchers say.
Nicky Pellegrino
Trigger effect

When Covid-19 vaccinations were first rolled out, vulnerable elderly people tended to be first in line. Then, as a younger demographic took their turn, there were reports from many women of what seemed like a strange side effect — changes to their menstrual periods. Some noticed cycle length was different after vaccination, others that their period was heavier than usual. By May 2022 in the UK alone, 39,839 women had reported  these sorts of changes.

Victoria Male, a senior lecturer in reproductive immunology at Imperial College London, first came across the phenomena when a colleague happened to mention her periods being heavier following the vaccine, just as they always were after she had her annual flu jab.

"If anyone should know about the reproductive side effects of vaccines, it ought to be me, but this wasn't something I'd ever really heard of," says Male.

She embarked on a small, unfunded study at the same time as other researchers also started looking into it. In Norway, a survey was conducted, while for Male and scientists in the US, menstrual tracking apps were a rich source of data.

"Most people use these apps because they want to know when to expect their next period, so cycle length is the key thing they record," Male says. "But some get into tracking every little thing."

The results have been reassuring. The science shows that any changes are typically small, short term and not a cause for concern.

Esta historia es de la edición January 14-20 2023 de New Zealand Listener.

Comience su prueba gratuita de Magzter GOLD de 7 días para acceder a miles de historias premium seleccionadas y a más de 9,000 revistas y periódicos.

Esta historia es de la edición January 14-20 2023 de New Zealand Listener.

Comience su prueba gratuita de Magzter GOLD de 7 días para acceder a miles de historias premium seleccionadas y a más de 9,000 revistas y periódicos.

MÁS HISTORIAS DE NEW ZEALAND LISTENERVer todo
First-world problem
New Zealand Listener

First-world problem

Harrowing tales of migrants attempting to enter the US highlight the political failure to fully tackle the problem.

time-read
3 minutos  |
September 9, 2024
Applying intelligence to AI
New Zealand Listener

Applying intelligence to AI

I call it the 'Terminator Effect', based on the premise that thinking machines took over the world.

time-read
2 minutos  |
September 9, 2024
Nazism rears its head
New Zealand Listener

Nazism rears its head

Smirky Höcke, with his penchant for waving with a suspiciously straight elbow and an open palm, won't get to be boss of either state.

time-read
2 minutos  |
September 9, 2024
Staying ahead of the game
New Zealand Listener

Staying ahead of the game

Will the brave new world of bipartisanship that seems to be on offer with an Infrastructure Commission come to fruition?

time-read
4 minutos  |
September 9, 2024
Grasping the nettle
New Zealand Listener

Grasping the nettle

Broccoli is horrible. It smells, when being cooked, like cat pee.

time-read
3 minutos  |
September 9, 2024
Hangry? Eat breakfast
New Zealand Listener

Hangry? Eat breakfast

People who don't break their fast first thing in the morning report the least life satisfaction.

time-read
3 minutos  |
September 9, 2024
Chemical reaction
New Zealand Listener

Chemical reaction

Nitrates in processed meats are well known to cause harm, but consumed from plant sources, their effect is quite different.

time-read
4 minutos  |
September 9, 2024
Me and my guitar
New Zealand Listener

Me and my guitar

Australian guitarist Karin Schaupp sticks to the familiar for her Dunedin concerts.

time-read
2 minutos  |
September 9, 2024
Time is on my side
New Zealand Listener

Time is on my side

Age does not weary some of our much-loved musicians but what keeps them on the road?

time-read
7 minutos  |
September 9, 2024
The kids are not alright
New Zealand Listener

The kids are not alright

Nuanced account details how China's blessed generation has been replaced by one consumed by fear and hopelessness.

time-read
4 minutos  |
September 9, 2024