Pearl Index and contraceptive safety

To evaluate the various means of contraception according to their safety or their effectiveness, one refers in a standard way to the "Pearl index". But what can this index tell us, how is it calculated and are these calculations really so reliable? We answer the most important questions on the subject of the Pearl Index.

What is the Pearl Index?

The Pearl Index attempts to give an indication of the safety of a contraceptive. It interprets the data collected for a certain contraceptive in such a way as to show how many women out of 100 have been pregnant despite using a contraceptive.

Thus, a Pearl Index of 2 indicates that 2 out of 100 women have become pregnant despite using a certain contraceptive. We then speak of a "failure rate" of 2%.

How is the Pearl Index measured/calculated?

The lower the Pearl Index, the higher the protection of a contraceptive. But how can we calculate the Pearl Index?

The calculation is based on 1200 months of use (100 women in one year) of a contraceptive. The index therefore makes it possible to know how many of these 100 women became pregnant in one year using the contraceptive in question.

Thus, we can say for example that if the Pearl index is 2, 2 women out of 100 have become pregnant in one year. If the Pearl Index is 0.05, one in 2000 women will become pregnant within a year.

Practical Pearl Index vs. theoretical

In general, the Pearl Index can be divided into two subgroups: the safety of the method (theoretical Pearl Index) and the safety of use (practical Pearl Index).

While method security is based on the principle of perfectly correct use of the contraceptive method, method security provides information on typical, daily use of a contraceptive method. Thus, factors such as forgetting to take, gastrointestinal diseases or even user errors are taken into account.

Pearl Index for hormonal methods

The contraceptive method most used by women is the pill. About 31% of women in Germany take it and swear by its effectiveness. In most cases, the Pearl Index of the pill is between 0.1 and 0.9, which also makes it one of the safest methods of contraception - according to the PI.

But this safety also comes at a high price, as the list of side effects is endless. Weight gain, thrombosis, hormone-related mood changes, tension in the breasts, migraines or nausea are just some of the many possible side effects.

Pearl Index for natural methods

How secure is the trackle?

Natural family planning (NFP) wants to do without the addition of hormones or chemicals. Unfortunately, natural contraception is still often thought to be too expensive and unsafe, or even requires surgery. However, these assumptions are wrong.

The safest method of natural birth control is the symptothermal method, whereby the birth control computer trackle also evaluate. It has a theoretical Pearl Index of 0.4 in method safety and is therefore - just like the contraceptive pill - below 1.

With regard to the safety of use, also called practical Pearl index, in which the errors of use are also taken into account, the sympto-thermal method gets a value of 1.8. In comparison, the safety of using the pill is 9.

The added benefit of trackle is that the risk of error in the application is greatly reduced by scanning the symptothermal method. In addition, day-to-day implementation is much easier than manual evaluation with a thermometer and cycle sheet.

The Pearl Index: a good orientation

The Pearl Index is a good way to compare birth control methods and their safety. Thanks to the Pearl index, it is possible to navigate through the diversity of contraceptive methods and to make a first choice. However, it is always advisable to keep in mind that: Whatever method of contraception you use, only correct use can guarantee safety and reliability. Therefore, for all questions relating to contraception, contact your gynecologist and ask him to advise you in detail in order to find the method that is right for you.

If you have any questions about contraception with trackle, do not hesitate to write to us at - we will be happy to answer your questions.