Long Covid patients say that symptoms can get worse just before or during their periods.
Researchers at Imperial College London found that 70 per cent of the 605 girls, women, nonbinary and trans people who have periods surveyed said their long Covid symptoms, such as breathlessness and fatigue, varied in intensity and form with their menstrual cycles.
Of those people, 62 per cent said their symptoms were worse in the days running up to or during their period – equating to 43 per cent of the total number surveyed.
These results provide valuable new information about both long Covid and the way it interacts with the menstrual cycle – about which little is known, in each case.
Victoria Male, the Imperial College London researcher behind the survey, said the findings could help to understand the causes of long Covid that may, in turn, lead to better treatments.
But she stresses that they need to be confirmed by a larger, more robust study – which she is now undertaking – pointing out that surveys such as the one she has just completed are by no means definitive.
So, for example, the new study will look at in detail at hormone levels. These are typically at their lowest just before and during a period, suggesting that falling oestrogen levels could worsen long Covid symptoms – a potential link highlighted by the survey that now needs to be tested.
“With a survey, people are recalling their symptoms and may not recall correctly, and the fact that we are priming them to think about their menstrual cycles at the same time may bias their responses,” Dr Male told i.
“That’s why the first step in this larger study will be to find out if people logging their symptoms in real-time, who do not have their menstrual cycles at the forefront of their mind, also have this pattern of worse symptoms in the pre-menstrual and menstrual phases of their cycles.”
The new study will draw on the 30,000 users of Visible, a free app to monitor and manage symptoms for long Covid and ME – and others who want to join to participate.
“Users are able to enrol directly into these studies, contributing their anonymised data to help scientists better understand the impact of Long Covid and hopefully help pave the way to finding new treatments,” according to Visible co-founder Harry Leeming.
Dr Male adds: “With many patients reporting exacerbated symptoms at different times of their cycles, it’s critical we delve into this area to steer future biomedical research,” – pointing out that the issue is particularly important because long Covid appears to disproportionately affect women, with estimates suggesting that 70 to 80 per cent of patients are female.
She says: “It’s very common to feel worse in the week leading up to your period and during your period, regardless of having long Covid. So one possibility is that this is a similar phenomenon.
“Another possibility is that the variation in long Covid symptoms over the menstrual cycle – if our findings bear out the survey data of course – is that this tells us something about the pathology of long Covid. Some people think that Long Covid might be an autoimmune problem, and certainly, there are autoimmune diseases that are worse in the pre-menstrual and menstrual phases of the cycle, like MS and IBD [inflammatory bowel disease]. If we find something similar going on with long Covid, that could tell us something about what is causing it.”
“Meanwhile, if we find long Covid symptoms do change over the cycle, that might suggest that taking hormonal contraception could ameliorate symptoms. We are actively looking into that, by asking Visible users about what contraception they use: we want to find out if people taking hormonal contraception report different patterns of symptoms,” she said.
Dr Male points out that separate research suggests that long Covid can affect the menstrual cycle – but that her study is concerned with the opposite situation, of the menstrual cycle impacting upon long Covid symptoms.