From what has been detailed so far it can be deduced that
|the stick reading method based on the increase of E3G is always valid for the purpose of pregnancy research as it ensures potentially fertile intercourses...
... since it still covers the green area of fig. 5. For this reason, the sticks with double indicators, although they are more expensive, are the only ones (unless other methods of observation of one's body, of course) that allow you to indicate early enough when to have potentially fertile intercourses.
While single indicator sticks are recommended to accurately identify the end of the fertile period, double hormone indicator sticks allow you to identify the beginning of the period with a higher probability of conception (this is a thing that sticks with single hormone indicator cannot to do).
In particular, if the increase in E3G is detected as soon as possible, and choosing to have intercourse every other day to maximize the chances of conceiving, it is preferable to have the first intercourse in correspondence with the fading of the left stick line, in particular as much as possible to close to the stick, so that the next intercourse would fall at or just before the LH peak, while still being adequately spaced from the first intercourse.
In this way, with the use of sticks alone, the days of the two most fertile intercourse could be identified and adequately spaced apart in order to maximize the number of spermatozoa present at the release of the oocyte.
It should be noted that outside the period with the highest probability of conception, it is not certain that you will not be able to conceive anyway!
In fact, the period with the highest probability of conception is included in the period indicated as the fertile period, the latter being however wider. In particular from fig. 5 it is seen that it begins 6 days before ovulation and ends one day after, as it considers that the life of the ovule is 24 hours. In the case of double ovulation, the graph could extend to an even longer period (up to two days later) as the two ovules are produced within 24 hours of each other at most.
The arguments made up to now on the timing of conception do not justify such a large fertile period (6 or 7 days) in fig. 5 but only the green area.
However, in fact, and fortunately, it exists thanks to the life expectancy of spermatozoa which is between 3 and 5 days, on average, but which can even reach 7 days.
It should also be noted that the extremes of the fertile interval have almost nil probabilities of conception, so if you are looking for a pregnancy in the shortest possible time, it is useful to identify the period with the highest probability of conception, even if it would be preferable to exploit the entire fertile period, in particular the days preceding the green area of fig. 5 (especially when a female child is desired, as detailed below).
In fact, exploiting the entire fertile window means "playing in advance", both to maximize the number of intercourse, and therefore of spermatozoa, and to better cover the window of uncertainty of the ovulation event, which is a statistical event of which the exact timing is not known (except for ultrasound scans).
As indicated in the example of figure 6, it should be observed that the more frequent use of the tests (for example one every twelve hours, instead of 24) allowed to detect both the increase in E3G and the LH peak twelve hours earlier (the evening instead of the next morning) compared to a use of the tests done for example every morning, or every 24 hours. In this way, both the beginning and the end of the most fruitful period are identified with greater precision.
Expert readers in the use of sticks know the trend of the lines in their fertile window. Once they have verified the increase in estradiol, they know that on average two days pass before the LH surge, so they will not do the sticks every day. In fact it is sufficient, once the increase in E3G is detected, that the LH surge directly occurs on the day known to them. This saves on the cost of testing.
For example, the first two tests in the figure below show the increase in estradiol before the peak, from this to the LH peak stick (third stick from the top), for example, as usually happens, two or three days (i.e. the stick was done directly on the day the LH peak was expected). The last stick only confirmed the end of the LH surge (which could be detected for more than a day) which corresponds to the day of probable ovulation.
The new stick reading criterion does not consider the search for the LH peak, that is the dark right line of the stick, but the fading of the left line, corresponding to the increase in estrogen before their peak.
At this point it is useful to know when to start using test sticks as a fertile period test. The suggested criterion is the following:
I) For regular cycles, the day on which to start using the stick to identify the fertile window must precede ovulation by 4 or at most 5 days (cycle length - luteal phase duration - 4 or 5 days)
II) For irregular cycles, the day to start sticking is = duration of the shortest cycle - the duration of the longest luteal phase - 4 or at most -5 days.
It is clear that the more irregular the cycle, the "wider" the fertile window will be, but this increase of width is not effective as it depends only on the uncertainty about the day on which ovulation will occur.
The uncertainty about the location of the fertile window may involve the use of several extra sticks before identifying the fading of the left line so in some cases it is advisable to use only the prospectus of your cycle (calculated and provided free of charge) having reports by days alternate (or at most two days no and one day yes) within the "widest" fertile window.
The calculation of a fertile window end of a "more wide" fertile window is free provided when you ask a montly cycle report in excel by firstname.lastname@example.org
The fertile week typically begins, and in particular referring to the case in figure 6, the day before (or at most the same day) of the first stick at the top, in which the left line is still dark. So the stick with the left line still dark would correspond to the second day of the fertile window. On the third day of the fertile window the left line typically fades, on the fifth fertile day the stick is repeated to check the LH surge, on the sixth day ovulation occurs, on the seventh day the egg dies and the fertile window ends.
From what has been specified it can be deduced that the sticks with double hormonal indicator, even if they cover the most fertile period, do not allow to exploit the entire fertile window.
In the considerations made so far, it has been assumed that ovulation has always occurred. However, it should be considered that there are cases in which the test detects an LH surge but ovulation does not occur. To be sure that the cycles are ovulatory, it is necessary to resort to ovulation monitoring with ultrasound or hormonal tests.
However, a valid alternative to monitoring or hormonal tests is the measurement of the basal temperature. For those who know the characteristic values of their basal temperature (which vary from woman to woman) it is sufficient to check (for at least 3-4 consecutive days and in the week following ovulation detected by the tests) if this maintains the high values, typical of a luteal phase of an ovulatory cycle. The permanence of a high temperature (3-4 days) is indicative of the increase in progesterone, a hormone still different from those detected by the stick and produced by the ovary (in particular by a gland called the corpus luteum) together with estradiol (fig . 7).
The graphs above within the fig. 7 shows the trends of the hormones produced by the pituitary, in the lower graph there is the trend of hormones produced by the ovary.