What is the Pearl Index
The so-called Peal Index is a value with which one tries to compare different contraceptive methods with regard to their safety. It can be traced back to the American physician Raymond Pearl and describes the proportion of 100 women who use a certain contraceptive method for a year and still become pregnant. This means that a Pearl Index of 1 for a contraceptive method means that out of 100 sexually active women who have used this contraceptive method for a year, one has become pregnant nevertheless.
Conversely, the lower the Pearl Index, the safer the contraceptive method. If the Pearl Index is z. e.g. 20, 20 of 100 sexually active women become pregnant within one year. The index can be calculated using the following formula: Pearl-Index = number of pregnancies x 12 months x 100number of months of use x number of women.
For unprotected sexual intercourse, the Pearl Index is 82-87 depending on the age of the women. At the time of menopause, the index drops to 0. For example, when condoms are used, the index is 4-20.
The Pearl Index of the Pill?
The Pearl Index of the pill must distinguish between the different types of pills. With the “normal” contraceptive pill, which contains estrogen +/- progestins as active ingredients and which is the most common and safest contraceptive method, the index is 0.1-0.9. This means that out of 1,000 sexually active women, 1-9 become pregnant within one year. The mini-pill, on the other hand, contains only one progestin. The Pearl index is therefore 0.5-3.
Mini pill
Unlike the contraceptive pill, the minipill contains only a progestin. It thickens the mucus in the cervix, as well as in the uterus itself, and alters it in such a way that the sperm are restricted in their mobility and implantation of the egg is difficult. The Pearl index is slightly higher than that of the pill at 0.5-3.
