Is it possible to measure the fertile days?

There are several ways to determine the fertile days approximately. There are a number of different ovulation tests (e.g. Clearblue), which determine the time of ovulation based on hormonal concentrations in the female urine (see above). This test is suitable for increasing the likelihood of pregnancy, as increased fertility is evident on the day of positive testing and the day after.

However, it is not suitable as a contraceptive method, as it does not provide information about the remaining fertile days and is also too inaccurate. There are other so-called contraception computers (e.g. Persona) which work on the same principle of hormone measurement. These also calculate, taking into account the lifespan of sperm, about 6 to 12 days in the cycle during which increased fertility is present.

The user is then recommended to use additional contraception. However, this method of contraception is far from being as safe as hormonal contraception using the Pill. Even if used correctly, pregnancy cannot be ruled out.

Other ways of measuring the fertile days are menstrual calendars and the symptothermal method. A menstrual calendar can be created to calculate the fertile days. Meanwhile, there are also tools on various Internet sites that calculate the fertile days based on various parameters that must be entered manually.

There are different methods to calculate the fertile days. One possibility is the so-called Knaus-Ogino method. This method assumes that, in a regular cycle, ovulation will almost certainly occur on the 14th day of the cycle.

To calculate this, the cycle lengths of the last 12 months should be known and there should be no major fluctuations in cycles. The first fertile day is calculated from the shortest cycle length minus 18 days. The last fertile day is the result of the longest cycle minus 11 days.

To illustrate this, here is a small calculation example: The fertile days are thus between the 10th and 23rd day of the cycle. According to this calculation, the infertile days are thus before the 10th and after the 23rd day of the cycle. However, the method is considered to be very unsafe and is by no means a reliable method of contraception.

However, it can be used to increase the probability of pregnancy.Besides the Knaus-Ogino method, the fertile days can also be determined with an ovulation calculator. This method can also only give an approximate indication of the fertile days. To do this, you need to know the first day of your period and the length of your cycle.

The first day of your period is the first day of your cycle. On the 14th or 15th day, ovulation takes place. About 3 to 4 days before and one day after ovulation are the fertile days.

Here, however, the information provided by different ovulation calculators varies. Some also indicate increased fertility up to 3 or 4 days after ovulation. In addition, the method is not particularly reliable, as in at least 40% of women ovulation does not occur with certainty on the 14th day of the cycle.

In addition, the length of the cycle often varies. To increase the chances of pregnancy, an ovulation calculator can be used, but it is not suitable as a reliable contraceptive method.

With a shortest cycle length of 28 days, the first fertile day on the 8th day of the cycle is 28 days minus 18 days = 10th day of the cycle
28 days minus 18 days = 10th cycle day
With a longest cycle length of 34 days, the last fertile day on the 23rd day of the cycle is 34 days minus 11 days = 23rd day of the cycle
34 days minus 11 days = 23rd cycle day
28 days minus 18 days = 10th cycle day
34 days minus 11 days = 23rd cycle day

There are a number of so-called ovulation tests that determine ovulation by means of the LH concentration in the urine.

This is the luteinizing hormone, one of the important cycle hormones, which is present in increased concentration during ovulation. There are both stripe tests, which indicate ovulation by means of a colour rash, and digital ovulation tests, which work with symbols on a digital display. In order to carry out the test, it is necessary to know the first day of the period and the last day before the next period starts.

This is how you can determine the length of your cycle. Enclosed with each ovulation test is a table, which shows when the test can be performed. For a cycle length of 28 days, this is, for example, the 11th day of the cycle.

Then ovulation is possible at the earliest. The test can therefore be carried out from this point on. It is advisable to perform the test at the same time every day.

It is advisable to use the morning urine, as the hormone concentration is highest here. Excessive drinking quantities should be avoided before the urine is discharged, as they can dilute the urine. The test then shows whether the LH concentration is elevated or not.

If it is positive, it means that the day of the positive test, as well as the following day, are the most fertile days of the cycle. The probability of pregnancy is increased on these two days. If the test is negative, it must be repeated the next day at the same time with a new test stick. The prices for such ovulation tests range from 10 to 40 Euros, depending on the manufacturer. They are also unsuitable as a contraceptive method.