Menstrual calendar (table): how to use? Check out apps

The human body is a very complex machine and this applies to all people in general, but especially to women. After all, we live with the possibility of a pregnancy.

Within this process, on a monthly basis, women deal with something that can be quite uncomfortable: the menstrual period.

Over the years, this cycle becomes something very common and we even get used to everything it causes. Within this process we also face bad symptoms, such as severe cramps and PMS.

In the beginning, the cycles can be quite irregular. For some women, periodicity never happens. To resolve these variations, some women look for medications such as birth control pills to help regulate them.

Other women, on the other hand, since the first cycle (menarche) have very straight cycles. Thus, every month they get an idea of ​​the day of menstruation and when the fertile period occurs .

An interesting way to calculate the arrival of menstruation is through the menstrual calendar.

The following text seeks to clarify how it works to know the duration of the menstrual cycle, the fertile period and ovulation. Good reading!


What is the menstrual calendar?

The menstrual calendar, or menstrual calculator, is a method used to try to more accurately predict when the next menstrual period or fertile period will be within the menstrual cycle.

For it to work, it is necessary for women to know how long the menstrual cycle lasts, the date of the first day of the last menstruation and the number of days of menstrual flow.

With this information it is possible to calculate when the next menstruation, fertile period and ovulation will be.

It is an easier account for those who have regular menstrual cycles, that is, the same interval of days between all cycles. However, even for women who do not have this periodicity it is possible to calculate.

Many women use the menstrual calendar to avoid pregnancy or to schedule a trip, for example.

Thus, they are able to know on which days they will be menstruating and from that they can schedule themselves.

On the other hand, other women use it just when they are trying a pregnancy, as the calculator helps to identify the most fertile days of the month.

This method, however, does not work for women using birth control pills or any hormonal contraceptive method.

The menstrual calendar considers the cycles in which ovulation takes place. In the case of women using the pill, this does not occur.

Women can follow this up with the use of apps that, in addition to alerting fertile days and menstrual flow, also function as a personal diary of the symptoms and patterns of the menstrual cycle.

What is the menstrual calendar for?

One of the objects of the menstrual calendar is knowing how to calculate your next period . Several reasons can lead women to use. Some include:

Know your own body

Using a menstrual calendar can be a good way to learn more about how your body works, as each woman has a different menstrual cycle.

For example, with the frequent use of menstrual calendar apps, it is possible to know the days when the fertile period happens and its symptoms. The same goes for the signs of PMS and menstruation.

It is also a way of ‘checking’ if everything is okay with health, monitoring delays or changes in the menstrual cycle.

To get pregnant or avoid an unwanted pregnancy

The menstrual calendar can be useful in these two ways. For women who wish to become pregnant, knowing which days the fertile period takes place can facilitate this process.

Thus, you will be able to reconcile sexual life with your partner according to the days when the probability of fertilization is greatest.

The same is true when the will is the other way around, to avoid pregnancy.

In addition to using contraceptive methods, women who follow their menstrual cycle and fertile period through the menstrual calendar may be more relaxed in relation to the days when the risks of pregnancy are greater or not.

To schedule visits to the gynecologist

Ideally, to maintain a preventive health care routine, women should seek to see a gynecologist at least once a year.

In these consultations, some exams can be done and that is why it is important to know when the menstrual cycle happens.

This way, it is possible to avoid that the menstrual cycle starts on the date of the consultation and, therefore, it is necessary to miss or reschedule.

Travel and special dates

The menstrual period can be very uncomfortable and even painful for some women. Being on the trip you have always dreamed of during these days can take away some of the fun or relaxation expected.

In places like beaches, being menstruating can be even worse, as the woman will have greater attention in relation to care, having to avoid going into the sea or in swimming pools, for example.

Thus, the menstrual calendar can be used so that the woman can calculate which days the menstrual period should happen and schedule trips according to those dates.

The same goes for special dates, when being menstruating can be a discomfort, such as weddings or anniversaries of courtship or marriage, for example.

How to calculate the next menstruation?

Calculating the menstrual cycle is simpler when the woman has a regular cycle, always having the same interval between one menstruation and another. This does not mean that the first day of menstruation will always happen on the same date.

The first day of the menstrual cycle , therefore, begins on the first day of the menstrual period. It should not be counted from a small bleed, such as a blot, but on the first day that the flow occurs.

The last day of the cycle is the day before your next period. Thus, the woman must write these two dates on the calendar.

For example, a woman who had her menstrual period beginning on May 1 and the next woman beginning on June 3, should count the days from May 1 to June 2 to know her cycle. In this example, the cycle would be 33 days.

How to calculate the irregular menstrual cycle?

It is possible to calculate the fertile period even when you have an irregular menstruation, but it is a little more laborious and inaccurate process. For this, it is necessary to have a kind of diary with some information of the menstrual cycle. First, you need to write down every day that your period has gone down for a year.

During this time, the woman must count every day between the first day of menstruation and the beginning of the next, so she will know the duration of each cycle, even if irregular.

At the end of that year, with all the information at hand, the woman must observe which was the longest and the shortest period. 18 must be subtracted from the shortest period and 11 must be subtracted from the longest period.

For example, a woman who had her longest cycle of 29 days and the shortest of 23 days would look like this:

29 – 11 = 18

23 – 18 = 5

It means that for this woman, from the 5th to the 18th of the month, the most fertile days take place. However, even with this monitoring, the account may fail. For those trying to conceive, one option is to use pharmacy tests to confirm ovulation.

For those who do not want to get pregnant, in addition to these calculations, the use of contraceptive methods is essential.

Menstrual calendar for contraceptives

There is no way to calculate the menstrual cycle and establish a calendar in these cases, as women who take the birth control pill do not have the menstrual cycle or fertile period, as they do not ovulate. The use of the drug is precisely to prevent this from happening.

Thus, they do not have the natural menstrual cycle, even when bleeding all month, periodically.

However, if contraceptive use is not regular, ovulation can happen and so can the chances of an unwanted pregnancy.

How to make a table?

To do the table, you need to know how long the menstrual cycle lasts, noting the days when menstruation starts and ends. In the case of a woman who has a menstrual cycle of 28 days, for example, to know the fertile period you need to count on the calendar 14 days after the first day of menstruation.

On that day, the woman will be in the fertile period, that is, having an ovulation.

However, some factors can interfere with this date, making it difficult to know precisely, so the fertile period is defined with a margin of error of 2 to 3 days before and after the fertile day calculated in the table.

Although for some women it is an alternative method of contraception and for others it is a way to get pregnant faster, it is necessary to be careful with the tablet.

As it helps to know the days that belong to the fertile period, it can be used for these two purposes, but for those who want to avoid a pregnancy the exclusive use of the table is not recommended .

Because it is not so safe and accurate, the tablet can be used as a complement to the use of condoms, birth control pills and other contraceptive methods.

How long does the menstrual cycle last?

The menstrual cycle has a different time for each woman, but it usually has 28 days and is divided into 3 phases, separated according to the hormonal changes that the body goes through during this period.

Considering a 28-day cycle, the division would be:

  • 1st to 7th day : where menstruation occurs, called the infertile period;
  • 8th to 19th day : fertile period;
  • 20th to 28th day : it is considered an infertile period, because the term of the eggs has passed and the woman’s body prepares for the next menstruation.

On the 14th day of the menstrual cycle, ovulation takes place, where the mature ovarian follicle, the protective layer of the egg, breaks and releases the egg (female gamete) that may or may not be fertilized by sperm (male gamete).

Ovulation is a process controlled by the endocrine system, where the hypothalamus gland is responsible for controlling the release of hormones that act in this phase of the menstrual cycle.

When the egg is not fertilized, from the first to the seventh day the flaking of the walls of the uterus occurs so that it prepares for the egg that will be released in the next cycle.

Although 28 days is a very common average, the menstrual cycle can vary between 25 to 35 days. Shorter or longer cycles, however, can be an indication that something is not right, such as polycystic ovary problems, which can cause this variation.

How to calculate the fertile period?

To calculate the fertile period, it is necessary for the woman to schedule the first day of each menstrual cycle for at least 6 months.

That way, it will be possible to know how many days each menstrual cycle lasted, time counted from the first day of menstruation to the day before the start of the next menstruation.

Knowing this, to calculate the beginning of the fertile period it is necessary to subtract 18 from the duration of the shortest cycle within those 6 months.

To discover the last day of the fertile phase, you must decrease 11 of the duration of the longest cycle.

For example, if the shortest cycle was 29 days, it means that the 11th day is the beginning of the fertile period (29 -18 = 11).

In the case of the longest 32-day cycle, the end of the fertile period will be on the 21st day of the cycle (32 – 11 = 21).

In this example, the woman who is trying (or not) to get pregnant should pay attention to the 11th to the 21st day of the menstrual cycle.

This method, which is based on the menstrual cycle and the fertile period, is called the table or table method .

Women who have a regular menstrual cycle, however, do not need to perform this subtraction. Considering a 28-day cycle, to know the fertile period a woman needs to count 14 days after menstruation.

That 14th day will be the peak of the fertile period, as this is when ovulation occurs. To know the fertile period, in fact, add up 3 days before and 3 days after ovulation.

Signs of the fertile period

The body sometimes sends out some signals that the fertile period is taking place. The most common ones involve the appearance of vaginal mucus, the presence of acne, pain in the lower abdomen, increased appetite and libido and a higher body temperature.

Normally, during fertile days, the woman will have a discharge that looks like an egg white.

When there is no clearer mucus, you can have it waterier.

These two characteristics allow sperm to swim more easily to the cervix. If this secretion is occurring, it is a sign that ovulation is near.

Other symptoms that are rarer, but that can happen, include feeling of swollen and painful breasts, feeling of weight gain, migraine and nausea.

Stages of the menstrual cycle

The menstrual cycle is divided into three phases: follicular, ovulatory and luteal. Understand:

Follicular phase

It is the first phase of the menstrual cycle that starts on the first day of menstruation and lasts, on average, between 5 to 12 days.

At this stage, the brain increases the production of follicle-stimulating hormone (FSH), which makes the ovaries able to mature the eggs.

During the second half of this phase, estrogen levels are also higher.

The increase in estrogen levels causes the endometrium (uterine lining) to create a thicker layer to prepare for the egg’s arrival.

Estrogen is also responsible for stimulating a greater production of cervical fluids (or vaginal mucus), which favors the passage of sperm to the fallopian tubes.

Ovulatory phase

This phase begins with the increase of the luteinizing hormone, responsible for selecting the most mature egg and for expelling it from the ovary. The stimulation of this hormone happens by increasing the levels of estrogen.

Once released, the egg travels through the tubes until it reaches the uterus. The egg normally survives 24 hours outside the ovary. While the sperm can last up to 5 days inside the woman’s body.

Thus, if the woman has sex without the correct use of contraceptive methods within a period of up to 5 days after ovulation, the chances of a pregnancy increase.

Luteal phase

The luteal phase is the last phase of the menstrual cycle and usually happens between the last 12 days of the cycle. During this period, the follicle begins to produce progesterone in greater quantities . Thus, you can prepare the lining of the uterus in the event of a possible pregnancy.

Estrogen levels also remain higher, which can cause symptoms such as changes in mood, swelling and tenderness in the breasts.

When fertilization occurs, the egg attaches itself to the walls of the uterus and the body begins to produce hCG.

This hormone is responsible for keeping the follicle producing progesterone and estrogen at high levels to preserve the lining of the uterus until the placenta forms.

On the other hand, when fertilization does not take place, the follicle shrinks within the ovary and the levels of the hormones estrogen and progesterone decrease.

In this way, the lining begins to be removed, the woman menstruates and the next menstrual cycle begins.

What can cause a delayed menstruation?

Some factors interfere with the regularity of the menstrual period and can delay menstruation. In these cases, before you think that the reason is a pregnancy, it is important to know what other factors influence the delay.

This is true both for women who are trying to conceive and for those who do not want a pregnancy at the moment. Both frustration and fear can be avoided when we understand a little more about it.

For example, during adolescence, from the first menstruation, it can take up to 2 years for it to start becoming regular.

Other factors that interfere are psychological issues, excessive physical exercise, mood and hormonal changes. Other common conditions that interfere with the menstrual cycle include:

Change in weight

Gaining or losing a lot of weight can cause our body to undergo a hormonal change and this ends up affecting the menstrual cycle, by interfering with estrogen levels.

This variation in weight can happen for several reasons and that is why it is important to have a medical follow-up if it is affecting your health.

The change in the menstrual cycle is one of the signs that it may be necessary to investigate further what is happening.

People who have eating disorders such as anorexia , for example, may have a messy menstrual cycle.

In such cases, it is important, regardless of this factor, to seek treatment and medical help.

Thyroid problems

The thyroid is an important gland in the production and secretion of hormones, including estrogen. Therefore, people who have a disorder in this gland or who take medication to regulate hormones may have interferences in the menstrual cycle.

Polycystic ovary syndrome

This is an endocrine disorder characteristic of causing an overproduction of androgen hormones (male). Among the signs of the disease is the fact that it makes the menstrual period irregular.


Viruses like flu or infections like cystitis or tonsillitis can cause some change in the cycle, as some drugs used to treat these diseases can interfere with menstruation.


The menopause , a condition in which there is ovarian failure, is a natural process for women. It usually happens around the age of 45 to 55, and may vary.

If menstruation is often delayed and the woman is within that age range, it may be an indication of menopause. In any case, it is important to investigate the cause with a gynecologist.

Stress and anxiety

Emotional problems can cause menstrual delay. Women who suffer from anxiety , depression or stress may have their cycle unregulated for these reasons.

Change in the use of the contraceptive pill

When the woman uses the contraceptive pill correctly she does not have a natural menstrual cycle, as ovulation does not happen. However, if it is a contraceptive pill with breaks, that monthly bleeding is expected.

Thus, it is important to know that some factors can interfere in the appearance of this bleeding, as in the case of changing the medication.


If your period is delayed it may be a pregnancy. To clear up the doubt, it is important to take a pharmacy or blood pregnancy test. If the result is negative, the woman should seek help from a doctor to investigate the cause.

The morning after pill disrupts the menstrual cycle?

Yes , because the pill of the following day has a large hormonal dosage and this ends up interfering with the menstrual cycle, which can make it unregulated during the month it was used. Therefore, it should not be used as a constant method of contraception, but in cases of emergency.

Women who maintain an active sex life and who do not intend to become pregnant should seek contraception with the guidance of a gynecologist.

Menstrual calculator apps

To facilitate this count, women can use some menstrual calculator applications.

There are several options that allow you to monitor when the menstrual cycle begins and ends, the days of PMS and the fertile period. Some examples include:

Get colic

This application divides the phases of the menstrual cycle by colors, which makes it easier to visualize fertile days, the peak between fertile days, menstruation days, in addition to signaling the symptoms and days when PMS may occur.

Another function is the games that the application makes available. They are thought of as a form of distraction for the days when colic is very uncomfortable.


It is a simpler application in relation to the visual, as it is not colorful like the Sai colic. The idea is to be simple and practical to use.

When creating an account on the app, the woman needs to provide some information in relation to the cycle, such as the date of the last menstruation, for how many days it occurs or if she has PMS symptoms, for example.

Other information that can be placed involves emotions, sleep, sex life, hair, skin which contraceptive method used.

In addition to being a menstrual calendar, Clue offers the option of sending reminders with the time to take the birth control pill.

It is a very useful function for those who have difficulty remembering to take it at the same time every day.

Maia – Periods, Fertility and Ovulation

It offers three main functions, that of monitoring menstrual periods, fertility and ovulation. Right when creating an account in the application, the user can choose the function that best fits her profile, which are:

  • Monitor the cycle and health;
  • Avoid pregnancy;
  • Try to get pregnant.

You can change the option you choose at any time. In sequence, the app will ask the woman to inform how long her menstrual cycle and flow days usually last.

It is also possible to note which symptoms are felt each day, such as the presence of itching, acne , swelling, tenderness in the breasts, mucus, nausea, bleeding, among others.

In addition, it is also possible to note emotions such as anxiety, tiredness , irritability, stress, calm, confidence etc.

Menstrual Calendar, Fertile Period and Ovulation

This application works as a personal diary of symptoms and emotions during the menstrual cycle. It is very simple, visually, but very intuitive. Like the others, it asks for some information about the cycle, such as the duration and days of menstrual flow.

As this day-to-day monitoring makes it possible to show patterns in the menstrual cycle. Thus, the woman will be able to get to know herself better, in addition to knowing the fertile days and the days when she will be menstruating.

People who have used the app and for some reason deleted it can back up the data when reinstalling.

Flo Menstrual Calendar, Pregnancy, Fertile Period

This is also an application made for those who want to monitor the menstrual cycle, and can be used in three main ways: to control the cycle without intending to become pregnant; to follow the cycle to get pregnant and, finally, for women who are already pregnant.

Like other apps, it asks for information about the date of the last menstrual period and how many days of flow occur.

It also shows if menstruation is late and on which days the fertile period occurs. The longer the usage time, the more accurate Flo’s menstrual calendar will be.

The menstrual calendar is an interesting method for those who want to know their own menstrual cycle better.

In addition to helping to know the days when menstruation will happen, it allows you to know the fertile days and the days when PMS symptoms may appear.

In this article we seek to clarify how it can help us on a daily basis. If you use the calendar or some of the applications, feel free to tell us in our comment space how it helps you!

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