pages titled "statistics" often imply a data set behind them. to be transparent from the outset: phasebloom has not commissioned or conducted a survey of menstrual health in the uk. this page instead explains, in general terms, the kind of information that is publicly available from bodies such as the nhs, and is honest about the limits of what we can responsibly state here.
general facts widely recognised in the uk
- a menstrual cycle is counted from the first day of one period to the first day of the next.
- cycle length is commonly understood to range from around 21 to 40 days, and this can vary from person to person and cycle to cycle.
- periods typically last for a number of days, and flow, duration and symptoms can differ considerably between individuals.
- symptoms such as bloating, breast tenderness, mood changes and fatigue in the days before a period are commonly reported, though the type and intensity varies widely from person to person.
- menstrual cycles change across a lifetime, including during adolescence, after childbirth and during the approach to menopause.
these points reflect general nhs guidance rather than any specific survey result, and we have deliberately avoided quoting precise percentages or figures that we cannot trace to a credible, current source.
why we're cautious with numbers
you will often see menstrual health statistics circulating online, such as specific percentages of people experiencing a symptom, or figures about menstrual product use or missed work or school days. many of these numbers originate from individual surveys with particular methodologies, sample sizes and dates, and can be easily misquoted or become outdated. rather than repeat a figure we cannot verify, we would rather point you towards primary sources.
where to find verified figures
for statistics you can rely on and cite with confidence, we recommend consulting the nhs directly, the office for national statistics, and peer-reviewed research indexed through resources such as pubmed. these sources publish methodology alongside their figures, which allows you to judge how robust a statistic really is.
an evolving page
as our understanding grows and as credible uk-specific research is published, we intend to update this page. our aim is never to be the source of a number that cannot be traced back to solid evidence.
our philosophy
at phasebloom, informed decisions begin with accurate information. we would rather this page read as "what we know so far, and where you should go for verified data" than present invented statistics as fact.