Menstruation is the most natural thing in the world. So natural, in fact, that it is often forgotten how complex a physiological process the menstrual cycle is. In this article, we have compiled the most important things that everyone should know about menstruation.

From a biological point of view, the gender of a person is defined at the level of chromosomes. We are either males with an xy chromosome pair or females with an xx chromosome pair. If a person is a woman by biological definition, it means that she has a uterus and ovaries. The main purpose of the menstrual cycle is to create a condition for conception in the uterus and ovaries. If pregnancy does not begin during the cycle, menstruation acts as a body cleanser. Menstruation allows the expired endometrium to leak out of the body once a month.

Therefore, periods are a sign that a menstruating person is of fertile age. Periods usually begin at the age of 10 to 16, and end at the age of 45 to 55. For Finns, the average age of onset of menstruation is 13 years and the average age for periods to end is 51 years. Between the onset and end of periods, between 400 and 500 mature eggs are released from the ovaries, i.e., that is how many periods menstruating people have on average during their lifetime. The timing of the start and end of menstruation is influenced by genetics and how much adipose tissue is present in the body, which produces ovarian function-fuelling oestrogen. If there is less adipose tissue in the body, menstruation may start later and end earlier than in those with more adipose tissue.

The length of the menstrual cycle can vary at different stages of life. Often at the onset of menstruation, the cycle may be irregular for the first 2-3 years. The cycle can also become irregular before the onset of menopause. The average cycle length is 28 days, but depending on physiological characteristics and life situation changes, its range can be from 23 to 35 days.

On average, there are 3 to 5 days of bleeding, but in general, the duration of menstruation ranges from 2 to 8 days. At the beginning and end of a period, spotting may occur for a few days. Changes in hormone levels can affect the amount of menstrual bleeding. For example, childbirth can increase bleeding, because the uterus grows as a result of pregnancy and this leads to more discharge of the endometrial surface.

Stages of the menstrual cycle

The menstrual cycle is calculated to start from the first day of menstruation. It is triggered when the hypothalamus, located in the brain, begins to produce the hormone GnRH. This hormone triggers the production of the hormone FSH, which stimulates the growth of follicles in the pituitary gland.

The actual cycle is physiologically divided into two stages. During the first 14 days of the cycle, the follicular phase takes place in the ovaries, and the growth phase, i.e., the proliferative phase, takes place on the mucous membranes of the uterus. At this point, oocytes begin to mature in the follicles located in the ovaries, one of which begins to grow into the so-called lead follicle. The follicle and ovaries secrete oestrogen, which, shortly before the middle of the cycle, causes a spike in the amount of LH, or luteinising hormone, produced by the pituitary gland. 36 hours after this hormone spike, ovulation occurs, meaning that the follicle bursts. This is when the egg cell is released from inside the follicle and begins its journey along the fallopian tube towards the uterus. Fertilisation occurs in the fallopian tube.

From ovulation to the onset of menstrual bleeding, it takes an average of 14 days. During the final cycle, the luteal phase takes place in the ovaries, and in the endometrium, the secretory phase. The lining of the uterus is now thick and secretory - meaning it is, ready to receive a fertilised egg cell.

If fertilisation has not occurred during the menstrual cycle, both oestrogen and progesterone levels drop towards the end of the cycle and the endometrium breaks down. This broken down endometrium is then shed from the body as menstrual bleeding.

Menstrual blood and the amount of bleeding

Menstrual blood consists of endometrial tissue, blood, bacterial flora of the uterus, and white discharge. Since the uterus is a sterile place, menstrual blood itself is also sterile and almost odourless. However, in favourable, warm and humid conditions, blood is also a good breeding ground for bacteria. Therefore, if it is absorbed into, e.g., a tampon or sanitary towel, it may start to smell unpleasant. The menstrual cup changes the attitude of many menstruating individuals to a more positive attitude towards menstrual blood, since the menstrual cup made of medical silicone is hygienic as a menstrual protection and does not act as a favourable breeding ground for bacteria.

The average amount of discharge during menstruation is 35 millilitres. The threshold of heavy bleeding is 80 millilitres and every third menstruator will experience heavy bleeding at some point in life. The amount of menstrual bleeding depends on factors, such as the individual’s genome, pregnancies, as well as tumours that weigh on the lining of the uterus. If you feel that your own menstrual bleeding is so heavy that it complicates life, it is worth discussing this with a gynaecologist.

In addition to the fact that the dead mucous membrane of the uterus is removed from the body along with menstrual blood, menstruation also has another important function. It cleanses the vagina and thus, for example, helps to stop the onset of any inflammations that begin there. On the other hand, the susceptibility to inflammation is high immediately after menstruation, so for this reason, taking care of intimate hygiene both during and after menstruation is especially important. 

Restrictions during menstruation

A menstruating person should be able to live a completely normal life during their period. If the menstrual bleeding is disturbingly heavy or the menstrual pain is so severe that you can't control it with regular painkillers, it's a good idea to talk about it with your gynaecologist. The amount of discharge can be influenced with various medications, such as hormone therapies, and often also with lifestyle changes. In case of menstrual pain, it is worth excluding, for example, the possibility of endometriosis.

For menstrual protection, you should choose the most hygienic, comfortable and reliable option. Non-breathable sanitary towels containing a lot of plastic are not only uncomfortable in use, many also consider them to be unreliable. On the other hand, tampons dry out the vaginal mucosa and can release harmful chemicals into the user's body. Since, with both sanitary towels and tampons, menstrual blood is in contact with the vaginal mucosa, they also make their users susceptible to various inflammations. The menstrual cup made of medical grade silicone is discreet and reliable in use. It is also an extremely hygienic menstrual protection, as the cup collects menstrual blood inside it and the material of the menstrual cup does not contribute to the growth of bacteria that predispose to inflammation.