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Changement brusque du cycle menstruel
Cycle menstruel

Why does my menstrual cycle change and go wrong?

You monitor your menstrual cycle regularly. You know the length of your menstrual cycle, know the length of your period, feel your ovulation and discern the symptoms of your PMS. But for some time now, you have noticed that your menstrual cycle is changing and seems to be going awry : its duration changes, your symptoms change, your periods vary... Why does your menstrual cycle change and what are the consequences? Find out the reasons and solutions in this article.

How does a menstrual cycle work?

The menstrual cycle is a natural process that occurs every month in menstruating people of childbearing age. It is organized in four phases:

  • Menstrual phase (also called “period” or “menstruation”): it generally lasts between 2 and 7 days,
  • Follicular phase during which an egg matures in the follicles of the ovaries. It begins at the same time as the menstrual phase and generally lasts 14 days,
  • Ovulatory phase : it corresponds to the release of the egg from the ovaries and lasts, for most women, between 24 and 48 hours,
  • Luteal phase : this last phase begins at the same time as the ovulatory phase and corresponds to the preparation of the body for implantation in the event of fertilization, in particular by producing the endometrium (uterine lining). It lasts 14 days.

The four phases of the menstrual cycle are orchestrated by hormones and induce different symptoms and signs that are more or less visible in the bodies of menstruating people. When the egg is not fertilized, the body expels it and the uterine lining: it's the period and a new cycle begins!

Irregular cycles or disruption of periods: how to tell the difference?

Before going further on the causes and consequences of a change in your menstrual cycle, it is essential to define exactly the framework of this cycle change. A change in your menstrual cycle does not correspond to irregular cycles; there is a difference between these two concepts.

Irregular cycles are cycles that do not fit the norm of menstrual cycles. These are menstrual cycles that are longer (they exceed 32 days), shorter (they are less than 24 days) or which have significant variations (which exceed 9 days apart). We have offered you articles on these different particularities of the cycle which can be completely benign or be symptomatic of a more serious problem.

A cycle which changes suddenly, as we talk about it today, is a cycle which has stabilized for several months/years and which changes suddenly for around 6 months. It is not impossible that your cycle changes occasionally (one cycle is different) for benign reasons that we will review later (stress, travel, etc.). It is when this change seems to take hold and repeat itself, over several cycles, that it is important to question yourself.

Consulting your doctor, your general practitioner or your gynecologist can then be a good way to understand what is happening and to carry out additional tests, if necessary.

What are the disruptions to the rules that we are talking about?

When we talk about the disruption of the rules, we are talking, for example, about changes:

  • Cycle length: longer or shorter cycles
  • Regularity of cycles: periods that suddenly become irregular
  • Period flow: very heavy or very light periods
  • Period duration: longer or shorter periods

These disturbances must be long-term (several cycles in a row) to require a consultation. Note that even if you had a cycle outside the average (very short for example) and its disruption makes it part of the average (it is closer to 28 days), it may be interesting to consult.

What causes a change in your menstrual cycle?

The menstrual cycle is particularly sensitive. It can vary for many reasons and be a symptom of different more or less annoying pathologies. This is why it may be interesting to follow your menstrual cycle and do not hesitate to consult your doctor or gynecologist if in doubt.

Hormonal changes

Menstrual cycles are organized by hormones , and in particular by progesterone and estrogen, the levels of which naturally vary enormously. In this context, hormonal changes or even hormonal disruptions can be the cause of sudden changes in your menstrual cycles.

1. Puberty

During puberty, a significant increase in sex hormones, such as estrogen and progesterone, is observed. The body begins to release eggs, which triggers the menstrual cycle. At first, the release of eggs may be irregular, which can make the first few years of menstruation rather unpredictable. Puberty generally occurs in young women between the ages of 10 and 15.

2. Menopause

Menopause is marked by a gradual decrease in estrogen. As this decline progresses, ovulation becomes more erratic and may eventually cease, leading to irregular cycles and then the complete cessation of menstruation. Menopause generally occurs between the ages of 45 and 55.

3. Polycystic Ovary Syndrome (PCOS)

Women with PCOS often have a hormonal imbalance characterized by elevated androgen (male hormone) levels and insulin resistance. This hormonal abnormality can hinder the ovulation process, leading to irregular cycles or even the absence of ovulation (anovulation).

4. Thyroid diseases

The thyroid produces hormones essential for regulating metabolism, growth and development. It also influences sex hormones and can affect the regularity of the menstrual cycle.

In hypothyroidism (when the thyroid is underactive), the release of thyroid hormone is reduced. This can lead to elevated levels of prolactin, a hormone that can inhibit ovulation.

Hyperthyroidism (overactive thyroid) can speed up metabolism and disrupt the balance of sex hormones, leading to irregular cycles.

His lifestyle

Did you know ? Your lifestyle can affect your menstrual cycles. As we have just seen, hormones are at work when regulating cycles. However, different habits can act on your hormones and disrupt your menstrual cycle.

1. Stress

In stressful situations, whether occasional or chronic, the body secretes several hormones, such as adrenaline, norepinephrine and cortisol. The latter can interact with the hormones which organize the menstrual cycle and thus modify it in a more or less brutal way. Have you been feeling anxious lately? Find our collection of articles dedicated to mental health and stress including our anti-stress routine:

Gapianne's anti-stress routine with an anti-stress balm, CBD oil and a relaxation herbal tea.


2. Sudden weight change

Significant and rapid weight gain, as well as significant and rapid weight loss, can suddenly change the menstrual cycle. Several elements come into play:

  • In the case of significant weight gain: obese people are able to secrete more androgens (male hormones) through adipose tissues, able to disrupt their hormones and the cycle. In addition, insulin resistance , sometimes caused by significant weight gain, can create hormonal imbalances.
  • In the case of significant weight loss: in the event of a strong caloric deficit , the production of sexual hormones drops: the body goes into pause. Cycles become rarer or even disappear (amenorrhea). Likewise, too low a body fat percentage can lead to hormonal imbalance.

3. Intense physical exercise

Intense and regular exercise can have an impact on the menstrual cycle, and some women may experience a temporary cessation of their periods, a phenomenon known as functional hypothalamic amenorrhea.

This can be explained by different factors:

  • Level of physical activity: When the level of physical activity is very high, it can disrupt the hormonal signals between the brain and the ovaries – but it is the hormones produced by the brain (LH and LSH) which are at the origin. origin of menstrual cycles.
  • Calorie deficit: If you burn more calories than you consume due to intense and prolonged training, this can lead to a calorie deficit. The production of sex hormones drops: the body goes on pause . Cycles become rarer or even disappear (amenorrhea).
  • Physical and mental stress: Physical stresses, such as intense and frequent workouts, can increase levels of the stress-related hormone cortisol. High levels of cortisol can also influence the menstrual cycle.
  • Body fat percentage: A low body fat percentage, often associated with intensive exercise, can disrupt the hormonal balance necessary for a regular menstrual cycle.

4. Travel

Because travel can be stressful and jet lag, the body and hormones can be disrupted in the months following a major trip.

Diseases, medications and medical procedures

Certain illnesses, medications and medical interventions, through their influence on hormones, can lead to the disruption of menstrual cycles . If this worries you, do not hesitate to speak with your doctor, your specialist or your gynecologist.

1. Diseases that impact the menstrual cycle

We mentioned, a little above, Polycystic Ovarian Syndrome (PCOS), is a health condition that influences the regularity of cycles. But it is not the only one. We can also cite:

  • Uterine fibroids: These are noncancerous tumors that develop in the uterus. Depending on their location and size, they can be painful and cause heavy periods, period pain, and irregular cycles.
  • Endometriosis: This is a condition in which tissue similar to the lining of the uterus grows outside the uterus, sometimes onto the organs all around it. It can cause intense pelvic pain, heavy bleeding and irregular cycles.
  • Blood clotting disorders: Certain bleeding disorders, such as von Willebrand disease, can cause heavy and prolonged menstrual bleeding. Your flow then changes significantly.
  • Eating Disorders (EDB): Eating disorders such as anorexia and bulimia, due to the calorie deficiencies and deficits they cause, can disrupt the menstrual cycle due to hormonal changes and nutritional deficiencies. Many anorexic menstruators are affected by amenorrhea.
  • Chronic illnesses: Certain chronic illnesses, such as diabetes and kidney disease, can influence the menstrual cycle.
  • Gynecological cancer: Cancers of the female reproductive organs, such as uterine or ovarian cancer, can cause changes in the menstrual cycle, such as abnormal bleeding.

⚡Don't panic. As we have seen, there are many reasons why your menstrual cycle can suddenly be disrupted (slow down, speed up, stop, etc.) and illnesses are therefore not the only ones! However, it is important to consult your doctor if you notice a change in your menstrual cycles so that you can have a diagnosis and answers to your questions.

2. Hormonal contraceptives

Hormonal contraceptives (hormonal pill, hormonal IUD or hormonal implant) have the function of interacting with the menstrual cycle. They deliver hormones into the body to block sperm access and prevent the egg from attaching to the uterus. Typically, they self-regulate the body's hormone doses and create an artificial menstrual cycle. This is why they disrupt the length of the menstrual cycle and disrupt the natural periods (different flow, different duration).

3. Psychiatric medications

Some psychiatric medications can impact women's menstrual cycles due to their effects on hormones and neurological systems. It all depends on the type of medication, the dose prescribed and taken, the duration of treatment and your particularities.

A few examples follow, but don't forget to consult your doctor if you experience sudden, unexplained changes in your cycle: he or she is your best contact and will be able to study your medical situation and provide you with answers.

  • Antidepressants and anxiolytics: These psychiatric medications, including selective serotonin reuptake inhibitors (SSRIs) and serotonin-norepinephrine reuptake inhibitors (SNRIs), could have an impact on the levels of hormones involved in the menstrual cycle . This can lead to changes in periods, such as heavier or lighter bleeding, menstrual irregularities, or even missed periods.
  • Antipsychotics: Some antipsychotics, especially those that act on dopamine receptors, can also affect the menstrual cycle , even producing false positive results on a pregnancy test. Hormonal imbalances induced by these medications could disrupt regular menstruation.
  • Mood stabilizers: These medications, used in bipolar disorder, such as lithium and divalproex, have the uncommon side effect of influencing the menstrual cycle.

4. Chemotherapy

Chemotherapy, a medical treatment often proposed in the context of cancer to stop the development of cancer cells, can seriously disrupt the menstrual cycle. It all depends again on the treatment, its duration and you.

Complete cessation of periods (amenorrhea), irregularity of cycles, lengthening or shortening of cycle length or even early menopause: all of these symptoms can occur during chemotherapy.

If you need to undergo treatment or are currently receiving treatment and notice any differences in your menstrual cycle, do not hesitate to speak with your doctor and your oncologist. They will be able to answer your questions and adapt the treatment or, if this is not possible, offer you options to manage these effects.

5. Hysterectomy

Hysterectomy is a surgical procedure to remove the uterus. It is most often performed for medical reasons (endometriosis, cancer). It causes the cessation of periods but not necessarily menstrual cycles : if you are not menopausal and the ovaries are not affected, their function will persist until natural menopause. You will therefore be able to experience symptoms related to your cycles while not seeing any bleeding.

Note, in the event of fallopian tube ligation, periods continue even though ovulation stops. In this context, the rules correspond to the expulsion of the endometrium (the uterine lining which develops in the uterus during the luteal phase) and more to the expulsion of the unfertilized egg.

Pregnancy and breastfeeding

This will certainly seem logical to you, but the last cause that can disrupt the menstrual cycle is none other than… pregnancy. Once the egg is fertilized and attached to the wall of the uterus, the sex hormones responsible for the proper functioning of the menstrual cycle work to stop menstrual cycles and facilitate pregnancy.

Once the baby is born, choosing to breastfeed most often has the effect of blocking the restart of the menstrual cycle: prolactin, which has the role of boosting milk production, also has the capacity to block the menstrual cycle.

Finally, after a pregnancy, continued or not by breastfeeding, menstrual cycles may change compared to what you knew before (longer, shorter, more or less painful symptoms, etc.). This phenomenon of change in postpartum menstrual cycles is also found in other situations: some women indicate that after taking hormonal contraception for a long time their natural menstrual cycles have changed (duration, symptoms, flow, etc.).

💡Please note: In certain very specific cases (notably during denial of pregnancy), menstrual cycles can continue despite fertilization and pregnancy until the end of the pregnancy, in the ninth month.

What are the consequences on her menstrual cycle?

The consequences of a suddenly disrupted menstrual cycle can be both physical and mental. This is why it is important to consult a healthcare professional if you notice that your cycles are suddenly changing.

On the physical level

At the physical level, the consequences of a disrupted and modified menstrual cycle on one's menstrual cycle are first of all the menstrual irregularity that results from it. Longer or shorter cycle, variable flow… The cycle becomes difficult to predict.

Even more, the symptoms of premenstrual syndrome (PMS) are either amplified or more varied: severe and unpredictable menstrual pain, swollen and painful chest, migraines, digestive disorders, fatigue, water retention... If we thought until now we knew his body, the cards are reshuffled and each cycle can bring its share of symptoms.

Finally, and this is often what brings women to consult, menstrual cycles that change suddenly can be synonymous with difficulty conceiving a child or even infertility . This is firstly because ovulation and the fertile window are less stable than in the context of regular menstrual cycles. Then, because some of the causes which lead to the disruption of periods and the menstrual cycle can be synonymous with difficulty in conceiving (in particular diseases such as endometriosis and PCOS).

On an emotional level

From an emotional point of view, a sudden disruption of menstrual cycles can cause anxiety and stress in menstruating people who experience it. This, for different reasons:

  • Feeling of uncertainty: not knowing when your period will come can be stressful and not easy to manage. Even more so if the periods are accompanied by complicated symptoms.
  • Hormonal variation and amplification of PMS: we were talking about it on a physical level, but the amplification of PMS and associated symptoms can also be mental. Anxiety and depressive episodes related to the menstrual cycle can become more violent.
  • Difficulty conceiving – if that's what you want: having difficulty conceiving a child can be particularly stressful, even guilt-inducing in some cases.

Is it serious if my menstrual cycle goes wrong?

The menstrual cycle is particularly sensitive to hormonal variations and thus to all the constraints that the body of menstruating people may encounter on a daily basis. The disruption of the menstrual cycle can thus be symptomatic of numerous causes, more or less serious. A stressful event in your life (moving, separation, birth, bereavement) can be the cause, as can more debilitating and serious illnesses such as endometriosis, PCOS or gynecological cancer.

How to manage and react to sudden change?

If you notice a sudden change in your menstrual cycles, the first thing to do is (it's easy to say, it's true) not to panic. A fluctuation in your menstrual cycle over a month can occur for many benign and natural reasons – a disruption is observed over several menstrual cycles.

The second thing to do is to take the time to observe your cycle and follow it for several months to notice the differences. You can use a period tracker app to help you note changes.

If this observation highlights a sudden change in your menstrual cycle which seems to be lasting, we recommend that you consult your general practitioner or gynecologist. They will take the time to interview you and review your entire medical profile to have you carry out additional examinations if they think it is necessary.

Finally, note that you can consult, with the aim of reassuring yourself, as soon as you observe a change in your menstrual cycle. However, your healthcare practitioner may invite you to monitor your menstrual cycle over a few months to confirm the changes–unless they notice other symptoms adding to the abrupt variation in your menstrual cycle.

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