Generality
Ovulation calculation is essential for the conception and prevention of unwanted pregnancies.
The period of ovulation <coincides with the moment of maximum fertility for a woman. Knowing exactly the day when ovulation occurs means increasing your chances of getting pregnant.
Because it is important?
Ovulation calculation requires knowledge of the rhythms and times of one's body; in particular, it focuses on the functioning of the menstrual cycle. In fact, this method makes it possible to identify the most fertile days and to understand when conception is most likely, in the case of sexual relations.
Ovulation and fertile period
To understand the calculation of ovulation some premises are necessary.
What is ovulation?
In every menstrual cycle, the most favorable days for conception coincide with ovulation and the period preceding it.
Generally, ovulation occurs mid-cycle, so - if the woman has a regular menstrual cycle of 28 days - it occurs 14 days before the next menstrual flow begins.
What happens during ovulation?
During ovulation, the ripened egg cell is released from the follicle that contains it and expelled from the ovary in the direction of the uterine tube (or oviduct). In this place it can be fertilized by a sperm of male origin.
fertile age
Every woman is born with a limited supply of egg cells, which gradually decreases over the years. Starting from puberty, ovulation is repeated every month, until reaching menopause, around the average age of 50 years.
The interval between puberty and menopause is called fertile age.
Ovulation calculation: times and duration
Ovulation occurs approximately every 28 days. After the onset of menstruation, the egg cell takes on average 14 days to reach adequate maturation and escape from the ovarian follicle to reach the tuba; this time interval coincides with the follicular phase. The actual ovulation corresponds, therefore, to the liberation of the oocyte from the ovary; the most fertile days coincide with those preceding this phase and with the moment in which the egg cell enters the oviduct and begins its journey to reach the uterus.
The "fertile window" and the calculation of ovulation
Conception is possible only in a few days of a woman's menstrual cycle.
- The moment of maximum fertility coincides with the day of ovulation, that is when a mature egg is released from the ovary, moves along the fallopian tube and is available for fertilization.
- The fertile period, however, is broader, considering that the egg cell expelled from the ovary can survive for about 24 hours, while the spermatozoa can remain viable in the female genital apparatus up to 72-96 hours from intercourse.
Indicatively, therefore, the "fertile window" in which it is possible for the egg to be fertilized begins 4-5 days before ovulation and ends 1-2 days later.
- It should be noted that the probability of a pregnancy increases significantly especially in the two days before ovulation and on the day on which it occurs .
Outside the "fertile window", however, conception is less likely.
What happens after ovulation
After ovulation, the menstrual cycle is completed by the luteal phase, which runs from the 16th to the 28th day; during this phase the inner wall of the uterus (endometrium) prepares to receive the egg, if conception occurs. If the oocyte is fertilized, the resulting cell divides (blastula) and implants in the endometrium 3 or 4 days after reaching the uterine cavity, ie 6-7 days from sexual intercourse.
On the other hand, if conception does not occur, menstruation will begin around the 28th day, with which the remains of the endometrium are expelled from the vagina.
How to calculate the day of ovulation
- Consider rhythm and length of the menstrual cycle . A good habit to adopt to assess the progress of your menstrual cycle - and to clearly identify the day when ovulation will occur - is to take notes monthly when menstruation begins.
NB: to calculate the duration of your cycle, the period of time from the first day in which the menstrual flow appears to the day preceding the start of the next menstruation must be considered.
- Ovulation occurs about two weeks before the next menstruation . If the menstrual cycle is repeated regularly every 28 days, ovulation will be around the 14th day (or 14 days before the next menstruation) and the "fertile window" will start on the 10th day.
NB: this is an illustrative reasoning and it is not possible to know with extreme certainty if the menstrual flow following ovulation will really arrive at the 28th day (in other words, it is not said that the cycle always occurs with the same interval of days ).
If the menstrual cycle is longer or shorter, it is important to consider that the first phase of the menstrual cycle (estrogen) is variable and may undergo oscillations, while the second phase (progestin) is more constant and lasts on average 14 days .
Even if the duration of the menstrual cycle is different from the average of 28 days, therefore, the fertile period will always be 14 days before the arrival of menstruation and in the 4-5 preceding it.
For example, in a 35-day cycle ovulation should occur on the 21st day after the end of menstruation; therefore, the "fertile window" will start on the 17th day.
In the case of shorter cycles, which appear, for example, every 21 days, ovulation should occur on the 7th day and the "fertile window" should start on the 3rd day.
- The day of ovulation and the two days preceding it are the most fertile. In general, the most favorable days for conception are six: the day of ovulation and the 5 days that precede it. The probability of a pregnancy increases, however, in the two days immediately before ovulation and on the day on which it occurs.
- If the menstrual cycle is 28 days, ovulation will take place around the 14th day, so the most fertile days correspond to 12th, 13th and 14th.
- In the event that the menstrual cycle lasts 35 days, ovulation occurs on the 21st and the most fertile period coincides with days 19, 20 and 21.
- If the cycle is 21 days, instead, ovulation is calculated in the 7th day and the most fertile days are the 5th, 6th and 7th.
NOTE : it should be remembered that the calculation of ovulation based on the date on which menstruation appeared is susceptible to error, even for women with regular menstrual cycles. In some months, in fact, ovulation can be unexpectedly anticipated or delayed compared to the foreseen day, making the simple numerical calculation vain.
When to have sex
Menstrual cycles can vary and are not always as regular as a watch; therefore, it can be difficult to predict exactly the day when ovulation should occur. Furthermore, the chances of becoming pregnant depend on many variables that can "mislead" the "fertile window", such as, for example, age, general health and lifestyle.
For the purpose of conception, therefore, regular sexual activity is important. In particular, having intercourse every 2 or 3 days, allows to cover as much as possible all the presumed fertile period and increases the probability of undertaking a pregnancy.
Signals to be reckoned with
Women with an irregular menstrual cycle, which varies from month to month, cannot rely solely on the calculation of days to understand when ovulation will occur.
In these cases, it is important to associate other methods to recognize the fertile period, such as the recognition of the signals of one's body.
During the ovulatory phase, in fact, changes occur that can act as indicators (see ovulation symptoms):
- The breast becomes tense and sometimes painful;
- The lower abdomen hurts and swells;
- Sexual desire increases;
- The senses and reflexes become more active;
- Vaginal secretions become more abundant, transparent and stringy.
Other methods to recognize ovulation
In addition to calculating ovulation, to understand when the "fertile window" is approaching, it is possible to use other methods, which include:
- Observation of changes in cervical mucus . A system to recognize when ovulation is about to occur is based on the observation of the quantity and appearance of vaginal secretions.
Due to the effect of estrogens, the production of cervical mucus increases in the pre-ovulatory period, which becomes evident with transparent losses. When ovulation is imminent, the secretions become very abundant and viscous and elastic, similar to egg white. From this change, ovulation could occur on the same day or within about 24-36 hours. In practice, cervical mucus "prepares the soil" for the possible fertilization of the mature egg cell, as it facilitates the passage of spermatozoa through the vaginal canal and promotes their survival. The secretions maintain these characteristics until the end of ovulation, so they become dense, sticky and diminish or disappear.
NB: it must be considered that there are some conditions, such as the presence of infections or polycystic ovary syndrome, which can alter the consistency of the mucus and make it difficult to observe it for procreative purposes.
- Record basal temperature daily . To identify fertile days, it is possible to use the daily basal temperature measurement in the morning, when you are just awake. It will be observed that, every month, there is a morning in which this parameter increases by about 0.2-0.5 ° C and remains constant for a few days until the next menstruation. This is explained by the fact that the basal temperature tends to increase immediately after ovulation due to the effect of progesterone. The increase in the basal temperature is also preceded by a slight decrease in the same; the last value, recorded before the increase in the basal temperature, corresponds to the day of ovulation. By recording these data on a graph or table and observing the analogies in the basal temperature trend, therefore, it is possible to determine in which period of the month ovulation occurs. It should be remembered, however, that the basal temperature may increase due to other factors, such as restless sleep, alcohol or hot drink intake, hormonal imbalances, severe stress and fever.
- Use ovulation tests . The ovulatory sticks warn when one is going through the fertile phase, measuring the hormonal levels in the urine. The test should be repeated for a few days, starting from the date when ovulation is most likely to occur. When a positive outcome is found, it means that the luteinizing hormone (LH) has reached a high concentration, so the ovulatory phase is imminent and we are in the most fertile moment of the cycle. If a pregnancy is desired, therefore, it is possible to have unprotected intercourse starting from the day the test is positive.
