Irregular menstruation: understand the causes, symptoms and types


What is irregular menstruation?

Before clarifying what irregular menstruation is, we need to understand what menstruation is and what is considered normal.

Menstrual flow starts at puberty, between 10 and 17 years of age. With this, the woman starts to ovulate, that is, she can already be a mother. The female body prepares for pregnancy, but when it does not, the endometrium (mucosa that lines the inside of the uterus) comes off, causing bleeding.

The regular menstrual cycle lasts 28 days, varying from 3 to 7 days and happens every month. However, only 15% of women have a stable cycle: the vast majority do not know the start or end date, which makes it difficult to recognize the fertile period . In such cases, the cycle varies from 21 to 40 days.



Amenorrhea is when there is no menstruation after 16 years of age or the absence of it for a period of three months, even if there is no pregnancy. It is not considered a pathology, but an indication of another disorder.


In oligomenorrhea, menstruation originates in an unpredictable and sporadic way. The cycles occur at intervals greater than 40 days. Like amenorrhea, it is not seen as a disease.


The menstrual cycle takes place in a very short period, about 21 days or less.

Hypermenorrhea or menorrhagia

It is characterized by dark bleeding, greater than 8 days and in abundant quantity, greater than 80 ml.

Metrorrhagia or uterine bleeding

Bleeding occurs outside the menstrual period. Metrorrhagia is the third most common disorder in gynecological consultations. Among the patients who have the problem, 20% are adolescents and half of the cases are adult women, between 40 and 50 years old.


Menometrorrhagia is noticed when there is intense and prolonged blood loss, both during and outside the menstrual period. It can develop through hypermenorrhea.


Amount of blood considered to be less than normal (below 30 ml) and lasting less than 3 days.


Menstrual disorder is a result of hormonal changes. It can be caused by several factors, from lifestyle to health problems. The main ones are:


In situations of stress , our body produces more of the hormones adrenaline and cortisol, leaving aside the production of estrogen (hormone responsible for ovulation and female aspects) and other reproductive hormones.

It is a natural response of our organism, linked to the survival instinct. The lack of estrogen interferes with the development of the uterine lining.


Flu, infections or more serious illnesses cause a defense reaction in a priority way, natural to our body, as well as in the condition of stress. Ovulation, in this case, can be extended or stopped.

Polycystic ovary

Polycystic Ovary Syndrome (PCOS) affects 20% of women during their reproductive phase. PCOS is defined by the alteration of the ovulatory process due to hormonal oscillation, contributing to the appearance of cysts.

The appearance of cysts during the ovular period is normal and disappears in the menstrual cycle. However, patients with PCOS do not eliminate them, causing the ovary to grow up to three times. As a consequence, ovulation occurs sporadically and with irregular cycles.


The thyroid is a gland responsible for producing thyroid hormones (T4 and T3), which are fundamental in the performance of the metabolism and functioning of almost all the organs of the body.

When a production disturbance occurs, menstruation is compromised. Among the symptoms of hyperthyroidism , there is bleeding with little flow and in a dispersed form. In addition, women may lose body mass, sweat excessively and experience insomnia .


The use of contraceptives and morning-after pills (PDS) can disrupt menstruation. The contraceptive, used to prevent ovulation or regulate the cycle, administered in the wrong way – if it is not indicated for your body or ingested at alternate times -, changes menstruation. Failure to take it also causes variations until the body regulates the hormone level on its own.

Antidepressants, blood pressure regulators and antiallergic agents can also affect the functioning of the menstrual period.

Exacerbated alcohol consumption

Ingesting alcoholic beverages in an accentuated way can cause unbalance or cause menstruation to disappear. This is because alcohol reduces the amount of estrogen and testosterone in the female body.

Body mass

Having a high body mass increases the production of estrogen, which generates a more bulky uterine lining and, consequently, a more intense menstruation.

The reverse is also harmful. Very thin people are subject to changes in menstrual flow, especially if the loss of mass happened quickly. In this case, the production of estrogen decreases, causing the reduction of ovulation, making menstruation unstable or extinguishing it.

Intense physical activity

Excessive physical activity can cause amenorrhea. Intense physical exercise decreases estrogen in the body, leading to the interruption of menstruation.

This condition can cause osteoporosis , a disease that leaves bones weak. Osteoporosis usually occurs in the elderly, but young women who have a heavy routine can develop the condition. Due to the fragility of the bones, fractures and posture problems are common.

Time change

Extreme time changes directly affect the menstrual cycle. The biological clock is deregulated as are the hormones responsible for menstruation.

Groups of risk


The first menstruation (menarche) occurs, on average, in girls aged 11 to 13 years. In 50% of cases, the cycles are anovulatory (when there are no eggs, created by the ovaries), causing changes in menstruation for up to two years. Adolescents may experience changes in the interval, duration and dosage of menstrual flow.

Post childbirth

After the baby is born, the woman may bleed for up to 40 days, which is not considered menstruation. Bleeding is the exit of the material surrounding the uterus during pregnancy.

In this period, the woman stops ovulating and there is no menstruation. The return time of the menstrual cycle is directly linked to breastfeeding, as the hormone prolactin, produced during breastfeeding, inhibits ovulation.


A woman officially enters menopause when she does not menstruate for a year, usually from the age of 45. Hormones undergo sudden and frequent changes, causing unstable menstruation.

Symptoms of irregular menstruation

Watch for signs that indicate irregular menstruation:

  • Menstrual cycle lasting longer than 8 days;
  • Interval greater than 35 days;
  • Interval less than 25 days;
  • Abundant blood loss;
  • Intense colic;
  • Variations of the cycle, that is, each month, it presents different days and flow;
  • Alteration of body mass, being more or less;
  • Marked growth of hair;
  • Irritability;
  • Lack of libido.

How is the diagnosis made?

Consult your gynecologist. Through examinations, it is possible to identify the cause and the appropriate treatment. They can be:

Pap smear or cervicovaginal smear

The pap smear, or cervicovaginal smear, as it is also called – consists of an external evaluation in the vulva followed by the vaginal insertion of an instrument called a speculum, in order to visualize the vaginal canal as well as the cervix. The test aims to detect possible diseases like cancer cervix of the uterus, HPV and other STDs.

Blood count

It is the analysis of blood cell levels, such as red blood cells, white blood cells and platelets. The aim is to diagnose possible anemias, leukemias and autoimmune diseases (when the immune system itself attacks healthy cells).

Hormonal dosages

Due to the importance of female hormones in regulating the menstrual period, their quantity in the bloodstream is measured to indicate the appropriate treatment.

Pelvic ultrasound

The assessment can be done in two ways: the first, called the suprapubic technique, is when the transducer (a mechanism that allows visualization through images) is placed on top of the lower abdomen skin; the second, known as transvaginal or endovaginal, occurs when the transducer is inserted into the vagina.

The procedures are intended to examine the perineal organs, such as the uterus, tubes, ovaries, arteries and veins.


Observation of the vagina and cervix using a device called a colposcope. It is done when the Pap smear results are abnormal. The test is also indicated to diagnose HPV.


If changes are found in the mucosa of the uterine wall, the doctor, using forceps, extracts the material for analysis.

Urine tests

This feature is used to investigate possible hormonal variations.

Is irregular menstruation curable?

If treated correctly, through medical monitoring and a healthy routine, irregular menstruation can be remedied.

In cases of dysfunctional uterine bleeding (SUD), the problem is resolved by lifestyle changes and / or hormone replacement. In more serious situations, the problem is resolved through surgery.


Know some treatments indicated to solve the problem:

Hormone replacement

Hormone replacement aims to repair the lack of amount of estrogen and progesterone (sex hormone that has the function of maintaining the balance of the ovarian cycle).

The way the replacement is made varies for each patient, and it can be through oral medication, gel or adhesive.

Combined contraceptive pill

The drug stops ovulation by means of the synthetic junction of estrogen and progesterone, preventing fertilization in case of unprotected sexual intercourse. It also transforms the cervical mucus (fluid produced by the cervix), disfavoring the permanence of the sperm.

In addition to preventing pregnancy, the pill is indicated for women who wish to regulate menstruation, as the contraceptive controls the hormonal dosage in the body, thus preventing menstrual disorders. Due to the absence of the egg, the blood comes in less quantity and, in some cases, presents a darker color.

Progesterone contraceptive pill

Indicated for women who have hormonal restriction, the contraceptive pill of progesterone or mini-pill, as it is also known, has only one hormone in its formula, the progestogen.

Just like the combined pill, it also prevents ovulation, however, with a weaker result. It has the function of changing the thickness of the cervical mucus, making it impossible for the sperm to enter, and modifying the structure of the endometrium (uterine wall), preventing pregnancy.

The woman menstruates regularly and in a reduced way. However, when taken on alternate days, the mini-pill can cause menstrual irregularity. It is also recommended for people predisposed to uterine tumors.


Estrogen replacement is recommended for women who are menopausal. Hormonal reduction at this stage contributes to the onset of cardiovascular disease and osteoporosis.


Testosterone restitution is also indicated for menopausal women and those with a lack of libido.

In the ovaries, the imbalance causes cysts within the organ. The problem can be noticed when there is irregular menstruation and severe pain.


Surgery is only indicated in more severe cases, such as the appearance of tumors and cysts. One of the interventions, in case of excessive bleeding and when the woman does not want to get pregnant anymore, is the so-called endometrial ablation , which consists of using heat to dismantle the inner layer of the uterus.


  • Medroxyprogesterone Acetate ( Acetoflux );
  • Algestone Acetophenide + Estradiol Enanthate ( Perlutan );
  • Didrogesterona ( Duphaston );
  • Ethinylestradiol + Levonorgestrel ( Cycle 21 );
  • Progesterone (Utrogestan, Evocanil );
  • Estradiol Valerate + Levonorgestrel ( Cicloprimogyna ).


NEVER self-medicate or stop using a medication without first consulting a doctor. Only he will be able to tell which medication, dosage and duration of treatment is the most suitable for his specific case. The information contained in this website is only intended to inform, not in any way intended to replace the guidance of a specialist or serve as a recommendation for any type of treatment. Always follow the instructions on the package insert and, if symptoms persist, seek medical or pharmaceutical advice.

Living together

Some changes in habits and practices can ease or even regularize menstruation:

Compression in the abdomen

Performing compresses with cold water in the abdominal area decreases the spacing of blood vessels, reducing the amount of blood.

Healthy eating

Eating habits influence reproductive functions, which makes the menstrual cycle linked to the amount of calories that the female body absorbs. When caloric reserves come into play, for example, the reproductive mechanism stops, that is, menstruation ceases.

Therefore, invest in foods that contribute to the functioning of the enzyme aromatase CYP, responsible for the balance of estrogens. Reddish fruits (strawberry and raspberry, for example) and colorful vegetables (such as carrots and squash ) should be added to the menu.

Vitamin C should also be consumed in abundance, as it helps in the production of hormones, in addition to having a relaxing and anti-stress effect, one of the main causes of irregular menstruation. Vitamin C can be found in foods like raw yellow peppers, orange juice and kiwi .


Some types of tea assist in the smooth functioning of the flow. Ingesting a mixture containing oregano, rue and cinnamon, for example, helps in the hormonal process. Horsetail, oak bark and dandelion, together, compress blood vessels because they have an astringent function and thus reduce menstrual flow.

Physical activity

The practice of physical activity generates beta endorphins (neurotransmitter located in neurons of the central nervous system and peripheral nervous system) that structure sex hormones. As a consequence, there is a readjustment in the cycle, as well as a reduction in cramps and an improvement in lubrication and libido.

In addition to these precautions, be aware of the symptoms of irregular menstruation, to inform your gynecologist more precisely:

  • How many days the menstrual cycle lasted;
  • Period between periods;
  • Bleeding intensity;
  • Flow appearance;
  • Other symptoms presented.

Related diseases

Irregular menstruation can indicate the appearance of other problems:


Women are the most affected by the disease, about 8 times more than men, with irregular menstruation being one of the symptoms.

The thyroid gland is responsible for giving us energy and assists in the good performance of our organism. When the levels of hormones produced by the thyroid are low, hypothyroidism occurs , when the opposite happens, it is called hyperthyroidism.

In addition to impairing the performance of the menstrual cycle, hypothyroidism can affect fertility. This happens due to two factors: the first one is due to anovulation, that is, the female body is prevented from releasing the egg; the second is to reduce the time the egg is fertilized, leading to expulsion during menstruation.


Myoma is a benign tumor hosted in the uterine muscle, both in the inner and outer regions. There is no justification for the onset of the disease, but what is known is that it is related to progesterone and estrogen.

75% of women are affected by the problem, however, half of them have no evidence. As the fibroid progresses, some discomforts may appear, such as heavy menstrual bleeding, long menstrual periods, urinary problems, abdominal, pelvic pain and during sexual intercourse.

The pathology can compromise the woman’s ability to get pregnant, as there may be deformation in the internal uterine part and increased inflammation.


Hormonal changes can be identified as responsible for the appearance of this type of tumor, which is usually benign. Among the symptoms presented by the disease is irregular menstruation, bleeding after intercourse or post-menopause, discharge with a bad odor and difficulty getting pregnant.

The dysfunction can become malignant in situations of obesity , high blood pressure or when the patient has cases of polyp in the family.

Hiperplasia endometrial

Endometrial hyperplasia is characterized by an increase in thickness of the mucous part that lines the internal part of the uterus (endometrium). The endometrium can reach up to 15 mm in thickness and varies in situations of pregnancy, menopause or menstrual period.

The appearance of the problem is linked to the excess of estrogen and a decrease in progesterone in the body. This change can happen due to several factors, such as diabetes , obesity and Polycystic Ovary Syndrome (PCOS).

In addition to changes in the menstrual cycle, women suffer from fluctuations in body temperature, changes in mood, increased body hair, abdominal and pelvic pain. If the woman becomes pregnant while ill, the risk of having cervical cancer and complications in pregnancy increases.


Irregular menstruation, by itself, is not a sign of cancer. However, in specific situations, you should be alert and consult the doctor. Check out:

  • Bleeding after sexual activity;
  • Have done the treatment recommended by the specialist and the problem still persists;
  • Women over 50;
  • Being in menopause and not menstruating for a year.

Some tumors are related to these symptoms:

Cervical cancer

Caused by the human papilloma virus (HPV), cervical cancer injures the inside of the uterus. It usually takes 20 to 30 years to advance. It can be aroused when the woman has sex with several partners without a condom , becomes pregnant many times or by the habit of smoking . Bleeding occurs after sex, pelvic pain and yellow or pink discharge, accompanied by a bad smell.

Endometrial cancer

In most cases, cancer can superficially penetrate the endometrial layer. Bleeding can appear in the pre-menopausal and post-menopausal periods, alternating its periodicity and intensity.

Some factors, such as high estrogen levels, little or no progesterone, diabetes and family history, contribute to the onset of the disease.

Ovary cancer

Ovarian cancer can lead to death. There is no exact reason for how the disease arises, however, some conditions favor its onset:

  • Excess ovulation or anovulation;
  • Family cases;
  • Heredity, that is, passed from mother to daughter;
  • Menstruating before the age of 12;
  • Never get pregnant;
  • Menopause from 50 years;
  • Hormonal treatment in menopause and fertility;
  • Polycystic ovary syndrome (PCOS);
  • Overweight;
  • Smoking;
  • Use of intrauterine device (IUD).

The symptoms are similar to those of other diseases, which makes diagnosis difficult. Irregular menstruation, back and abdomen pain , digestive problems are some indications. The high mortality rate is associated with the woman’s delay in feeling the signs. Therefore, consult your doctor regularly.

How to prevent

It is difficult to determine habits that prevent changes in the menstrual cycle. In general, having a balanced diet and exercising is essential to keep the body functioning. Some women even use birth control pills to control menstruation.

Common questions

How to know the fertile period with irregular menstruation?

The fertile period in women with regular 28-day cycles occurs in the middle of the cycle, that is, 14 days are counted from the date of the last menstruation. For those who have unregulated menstruation, the analysis should be made from the last 6 months. The calculation must be based on the shortest and longest cycle. See how to determine your fertile period here .

Can you do a patch on irregular menstruation?

As the estimate of the fertile period is not certain, it is not recommended to make the table in these cases.

Irregular menstruation increases the chances of getting pregnant?

Due to the difficulty in knowing the fertile period, if the woman has sex and does not use contraceptive methods, the risk of pregnancy is greater.

How many days late is enough to take a pregnancy test?

With 1 or 2 days of delay in the menstrual cycle it is already possible to do the test. For a more reliable result, wait at least a week.

Is excessive menstrual bleeding dangerous?

Menstruating in large quantities causes loss of iron, a mineral linked to hemoglobin, responsible for transporting oxygen to the cells. As a consequence, the woman may develop anemia and show signs of weakness and tiredness . In more severe cases, the patient requires hospitalization and blood transfusion.

Irregular menstruation affects most women, so don’t panic! However, be aware of the symptoms explained in the post, as it can be indicative of more serious problems.

Talk to other women and if you have any questions, please contact us!