How does the menstrual cycle work?

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The woman's menstrual cycle begins with menarche: the first menstruation.

With it our fertile stage begins, women become cyclical and leave behind the linear hormonal pattern of childhood to enter the hormonal dance. This will change depending on the day and will accompany us until the arrival of menopause.

Going through the fertile stage without knowledge can be overwhelming, we need to understand the physiology of the menstrual cycle. As women, knowing our own cycle empowers us, it gives us so much information about what is happening inside us that allows us to anticipate and take charge of our health and well-being.

Women experience constant changes throughout our fertile stage, physical, mental, emotional and energetic changes. Our nature is cyclical and ignoring it can give us more than one headache.

Menstruation will be our life partner for approximately 40 years. It deserves our full attention, don't you think?

1. What happens during the menstrual cycle?

The menstrual cycle occurs thanks to the joint work of the brain, the ovaries and the uterus that communicate with each other through hormones. Each cycle begins with menstruation and ends just before the next one occurs. It is continuous, which means that it happens over and over again throughout a woman's fertile time and culminates with the onset of menopause.

The menstrual cycle is a hormonal swing that lasts approximately 28 days (normal menstrual cycles vary between 25 and 36 days). During these days the body prepares for a possible pregnancy and if this does not happen, menstruation occurs and starts again.

Hormones regulate the menstrual cycle in each of its phases: the follicular phase, ovulation, and the luteal phase . Menstruation can be considered a phase due to its own characteristics, but it is actually within the follicular phase.

1.1. follicular phase

This phase begins on day 1 of menstruation and ends with ovulation , on day 14 in the case that we are talking about a 28-day cycle, not all of them last the same.

During this phase, follicle-stimulating hormone (FSH) induces in the ovary the stimulation of a group of follicles (cells that contain immature ovules inside) for their maturation, although only one will eventually become a mature ovule. These follicles release large amounts of estrogen which stimulates the thickening of the endometrium in the uterus and in turn prepares the ovary to release the egg.

1.2. Ovulation

When luteinizing hormone (LH) levels reach their peak, the mature egg is released, it detaches from the follicle and leaves the ovary. The fimbriae drag the ovum and take it to one of the fallopian tubes. Estrogen levels peak just before ovulation occurs and decline soon after.

This phase lasts only a few hours , between 16 and 24 hours approximately.

1.3. luteal phase

It begins just after ovulation and ends with the arrival of menstruation .

The follicle that contained the mature ovary inside becomes the corpus luteum and begins to produce progesterone . Estrogen levels decrease, making progesterone the leading hormone.

If pregnancy does not occur, this corpus luteum disintegrates and stops producing progesterone. This serves as a support for the endometrium and, since there is no progesterone, the endometrium is shed, causing bleeding and thus a new cycle begins.

Phases of the menstrual cycle

As you can see, during the first part of the cycle (follicular phase) there is a predominance of estrogens over progesterone and, in the second part (luteal phase) the opposite happens, progesterone becomes the main hormone. When this hormonal fluctuation occurs correctly everything works well. The problem arises when this balance is lost and its phases are altered.

The most common disorders associated with the menstrual cycle are: long and irregular periods , dysmenorrhea (sharp pain during bleeding), the well-known premenstrual syndrome normally caused by excess estrogen or amenorrhea , which is the absence of a period.

2. Is my cycle ovulatory?

Now you know that a woman's cycle is much more than a few days of bleeding. Everything starts earlier and ovulation plays a fundamental role because without it there is no real menstruation.

Bleeding does not always indicate ovulation, there are anovulatory cycles in which the egg has not been detached from its ovary, therefore, fertilization cannot take place but there will be bleeding because the endometrium must be detached.

Anovulation can be circumstantial or chronic . Many times when this happens it is accompanied by irregularities in the cycle such as amenorrhea (absence of periods) and it is easy to detect it but it can also happen that menstruation takes place regularly and we do not realize anovulation until we do not want to get a pregnancy.

There are several strategies to detect if we are ovulating. We can do an ovulation test, a blood test to measure the level of progesterone, a pelvic exam, an ultrasound...

But this article is about connecting with ourselves, about self-exploration and self-knowledge. The body sends us signals that we can identify and interpret and with them we can know when our most fertile days are, when ovulation occurs or when there is more presence of estrogen/progesterone.

These signs are basal body temperature , cervical mucus , and the position of the cervix (cervix).

2.1. Basal temperature

It increases with the presence of progesterone and we know if ovulation has occurred because it will increase between 0.2ºC and 0.5ºC compared to the first half of the cycle. The only drawback is that it is necessary to take your temperature as soon as you wake up, always around the same time and it requires a daily control to be able to identify it.

Basal temperature

2.2. cervical mucus

It varies throughout the cycle, with the greatest amount of mucus appearing just before ovulation. Estrogen-dominant cervical mucus, the fertile mucus , is slippery and transparent like egg white. It has a suitable pH for the survival of spermatozoa and allows their passage.

While progesterone-influenced cervical mucus creates a thick plug that inhibits the passage of sperm, it is characterized by an absence of discharge.

23. The position of the cervix

It also experiences variations during the cycle when you are about to ovulate. If it is in a high position it is soft and humid and with ovulation it opens. After ovulation its position is lower, it is harder and drier and the neck closes.

This helps you know when you are most fertile and when you may be ovulating.

Knowledge gives us opportunities to get to know each other a little more every day and the body does not stop sending us signals for us to interpret and analyze, we just have to pay attention to them.

3. Signs of a healthy menstrual cycle

Knowing the menstrual cycle is entering the path of self-exploration, in which we must pay attention to small details. Not all cycles are the same and the sensations may vary from one to another, but there should be a certain trend or normality between cycles. Irregularities can indicate that something is wrong.

3.1. Characteristics of a healthy menstrual cycle

  • Absence of clots.
  • The duration of bleeding is 3-5 days.
  • There is a loss of between 20-80 ml of bleeding per cycle.
  • The duration of the cycle is between 24 and 36 days.
  • Absence of pain. You may notice a slight discomfort due to the contraction and relaxation that occurs in the muscles of the uterus during the expulsion of the endometrial tissue, this is a physiological action and it should not hurt.
  • Absence of premenstrual syndrome. We can have different sensations days before menstruation. When estrogen drops, so does serotonin and we can feel more tired or more emotionally sensitive, but it shouldn't be painful or exaggerated.

These are only guidelines or indications that can alert us to possible irregularities. If during a cycle not all of them occur, it only reveals aspects that we can improve for the next cycle, but if you see that this is repetitive in your cycles then something is wrong, we would have to see what the cause is.

Do not compare your cycle with that of other women either, keep in mind that various factors influence it, lifestyle, diet, physical exercise, stress or rest, among others. On some occasion you may have experienced a change or irregularity in your cycle due to the simple fact of having gone through a stressful time in your life. The body is susceptible to changes and it lets us know, it can manifest itself in different ways and this is one of them.

Menstrual cycle

4. Conclusion

Do you know when your last period was and how many days it lasted? If you don't know, maybe it's time to pay attention.

The menstrual cycle is an indicator of health and we should not ignore it. It is something natural and physiological in women, as is going to the bathroom every day. I'm sure that if you go three whole days without going to the bathroom, you start to worry or at least get uncomfortable about the situation and you try to fix it because you know that something is wrong.

The same thing happens with the cycle, if something does not go well, it must be solved.

Talking about menstruation until not long ago was a taboo subject, something that was not talked about. This has meant that due attention has not been paid to it for many years and that many problems or symptoms associated with menstruation have been silenced due to concern or ignorance. But this is long gone and today we know that it is a symbol of health as it is to go to the bathroom every day ;)

Fem Balance Be Levels



-Dasharathy SS, Mumford SL, Pollack AZ, Perkins NJ, Mattison DR, Wactawski-Wende J, et al. “Menstrual bleeding patterns among regularly menstruating women. Am J Epidemiol.” Am J Epidemiol 2012 Mar 15;175(6):536-45

- Sweet, MG, Schmidt-Dalton, TA, Weiss, P.M,. & Madsen, KP (2012). Evaluation and management of abnormal uterine bleeding in premenopausal women. American family Physician, 85, 35-43

-Human cervical mucus. II. Changes in viscoelasticity during the ovulatory menstrual cycle. Fertil Sterile 1977 Jan;28(1):47-52.

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