How much of our lifetime do we actually spend having periods?
How many periods does a woman have in her lifetime – and how many days does that add up to?
Let’s do some period maths.
How many periods does a woman have in her lifetime?
There is no single number that applies to every woman.
The age at which periods begin, the age at which menopause occurs and the regularity and length of the menstrual cycles in between all vary from person to person.
Pregnancy, breastfeeding, hormonal contraception and individual cycle length can also affect how often menstruation actually occurs.
If we simplify things and assume around 12 periods a year over roughly 40 reproductive years, we get:
12 × 40 = 480 periods
So, 480 periods is not a medical average. It is a deliberately simplified calculation designed to illustrate something we can easily overlook: menstruation accompanies women through a substantial part of their lives.
How many days does this add up to?
Now let’s assume five days of bleeding per period:
480 × 5 = 2,400 days
That works out at around 6.6 years spent menstruating.
Quite a number.
But it only tells part of the story. Because our menstrual cycle doesn’t just affect us on the days we bleed.
The menstrual cycle doesn’t begin and end with your period
When we talk about our “period”, we tend to think first about the days of menstrual bleeding.
But the menstrual cycle involves much more than that.
In the days before menstruation begins, some women experience a range of physical and emotional changes. Premenstrual symptoms can include:
- changes in appetite and food cravings
- breast tenderness
- bloating
- tiredness
- headaches
- irritability
- mood changes
For some women, these changes are barely noticeable. For others, they can have a considerable impact on everyday life. This is referred to as premenstrual syndrome, or PMS for short.
Which raises an interesting question:
If our period maths included not only the days of bleeding but also the days on which we experience premenstrual symptoms, how much of our lives would actually be affected by our cycle?
Can we simply add ‘PMS days’ to the calculation?
It might be tempting to add, say, five premenstrual days to every cycle and simply double our 6.6-year calculation.
But that would be misleading.
Not every woman has premenstrual syndrome (PMS). Not every cycle is the same. And even among women who experience premenstrual symptoms, their nature, duration and intensity can vary considerably.
PMS also means more than simply feeling a little different before your period. The term describes a recurring pattern of physical and emotional symptoms associated with the menstrual cycle that can affect everyday life.
So there is no scientifically meaningful number for “years spent with PMS” that we can simply add to our calculation.
What we can say is that the effects of the menstrual cycle can extend well beyond the days of menstrual bleeding.
6.6 years of periods – yet we still don’t talk about them enough
Our period maths is, of course, only a thought experiment.
2,400 bleeding days, or 6.6 years of menstruation, will not apply to every woman. Reproductive lifespan, cycle length and the actual number of periods vary considerably between individuals.
But the calculation makes something visible that otherwise remains rather abstract.
The menstrual cycle accompanies many women for decades.
And it is not just about bleeding.
Energy levels, wellbeing, appetite and physical or emotional experiences may all change throughout the cycle.
Perhaps, then, we should spend less time expecting women to make their cycle as invisible as possible.
And a little more time understanding what is actually happening in the body throughout all those years.
Because something that accompanies us for decades is hardly a footnote.
It deserves our attention.
Frequently asked questions about periods, PMS and your menstrual cycle
How many periods does a woman have in her lifetime?
There is no universal number. The age of the first period and menopause, cycle length, pregnancy, breastfeeding, hormonal contraception and other individual factors can all influence how many periods a woman experiences. Figures of several hundred periods over a lifetime are therefore best regarded as illustrations rather than fixed biological averages.
How many days of her life does a woman spend on her period?
Using our simplified calculation of 480 periods with five days of bleeding each gives 2,400 days – approximately 6.6 years. The actual number can, however, vary considerably from woman to woman.
How long does a period normally last?
The duration of menstrual bleeding varies between women and can also change at different stages of life. Individual variation is therefore normal, although significant or persistent changes should be discussed with a healthcare professional.
When do PMS symptoms occur?
Premenstrual symptoms typically occur during the time before menstruation and usually improve around or shortly after the period begins. The type, duration and intensity of symptoms
Reference
Nabhan AF, Mburu G, Elshafeey F, Magdi R, Kamel M, Elshebiny M, Abuelnaga YG, Ghonim M, Abdelhamid MH, Ghonim M, Eid P, Morsy A, Nasser M, Abdelwahab N, Elhayatmy F, Hussein AA, Elgabaly N, Sawires E, Tarkhan Y, Doas Y, Farrag N, Amir A, Gobran MF, Maged M, Abdulhady M, Sherif Y, Dyab M, Kiarie J. Women’s reproductive span: a systematic scoping review. Hum Reprod Open. 2022 Feb 11;2022(2):hoac005. doi: 10.1093/hropen/hoac005. PMID: 35280216; PMCID: PMC8907405.
