Menstruation is often described as a monthly cycle — but what does the phenomenon actually entail? What does “monthly” mean in terms of specific numbers and what are the variations that fall within the norms? Read on to find out.
What is menstruation?
To better understand the nature of possible variations in the length and frequency of the menstrual cycle, it helps to know the mechanics of the phenomenon itself. Menstruation – also referred to as period – is “a normal vaginal bleeding that occurs as part of a woman’s monthly cycle.”1 During the cycle, the body prepares for a potential pregnancy, and when there is none, the “preparatory” lining of the uterus is shed through the vagina2. The cycle is counted from the day the bleeding occurs (the first day of the period) to the day before the onset of the next bleeding3.
What can be considered a normal period cycle length?
The very word “menstruation” has its roots in the Late Latin word “menstruus”, which means “monthly” — this, however, might seem rather vague, as the exact length and frequency of the cycle depend on various factors, both inherent and external.
So what is considered to be normal? In general, menstruation occurs every 21 to 35 days and lasts from 2 to 7 days5 — the time range is therefore quite broad and accommodating. Interestingly, there may be some noticeable period changes that come with the passage of time — whereas the menstrual flow is said to be longer in the initial years after the first period, it often becomes shorter and more regular with age, and tends to get somewhat irregular before menopause6.
What should we watch out for?
Since every person’s body is unique, what is “normal” can vary from person to person too, at least to some extent. As we can read on Mayo Clinic’s website, Your menstrual cycle might be regular — about the same length every month — or somewhat irregular, and your period might be light or heavy, painful or pain-free, long or short, and still be considered normal. Within a broad range, “normal” is what’s normal for you1.
It is important, however, to always consult a specialist if there are any major changes in the cycle, as they can be symptoms of some more serious issues2. While it is true that some anomalies occur due to less harmful or easily manageable causes (such as stress, using certain forms of contraception, or excessive workout), they can also be indicative of polyps, fibroids, absence of ovulation, various infections, or even tumours3. In particular, among the irregularities that should alert us are:
- periods shorter than 21 days or longer than 38 days,
- bleeding between the respective cycles,
- missed periods,
- heavy bleeding (that necessitates changing a given menstruation product every two hours or often)4.
All in all, the menstrual cycle length is influenced by numerous factors, and some minor irregularities can usually be perceived as normal — but should anything become a matter of concern or raise any doubts, it is always advisable to consult a specialist.