Nowadays, there are many contraceptive methods available to us, all of which offer varying degrees of safety against unwanted pregnancy, but never one hundred per cent. The safety of a method can be described using the method and application safety as well as the Pearl Index.
Condoms, female condoms and dental dams offer additional protection against other sexually transmitted infections (STIs) and should therefore also be used if in doubt.
We would like to offer a brief overview of the various methods.
Safety of contraception
The Pearl Index indicates how many out of 100 women with a particular method become pregnant on a statistical average over a year with regular sexual intercourse.
The lower the Pearl Index, the safer the method. With regular sexual intercourse without using a contraceptive method, the Pearl Index for women aged between 19 and 26 and 35 and 39 is 82, and between 27 and 34 it is 86-87. Fertility ends with the menopause from around the age of 50.
The Pearl Index does not take into account relevant parameters such as frequency of sexual intercourse or sample size. As a result, the index is only of limited value for new contraceptive methods, especially if it is published by the manufacturer. The more frequently and long-term a contraceptive method is used, the more accurate the Pearl Index becomes.
As the success of many methods, i.e. the Pearl Index, depends on the people using them and their knowledge, experience, reliability and motivation, it can vary greatly depending on the study.
The more recent specification of method and application safety attempts to improve the significance of the Pearl Index. It takes into account that the safety of most methods depends crucially on the correct application.
The failure of contraceptive methods is usually caused by application errors. This is why the difference between method safety, i.e. failure despite optimal application, and application safety, i.e. the practical consideration of application errors, is so great for most methods.
Many contraceptives therefore have a Pearl Index X – Y, where the method safety is the smaller number X and the (actual) application safety is the larger number Y.
Hormonal contraception
Pearl Index:
– Method reliability: 0.3
– Application security: 9
How it works: The daily preparation contains progestogen (corpus luteum hormone) and oestrogen. The two hormones prevent ovulation and thicken the uterine mucus, making it more difficult for sperm to penetrate. The pill can be taken continuously or with a 7-day break.
Frequency of use: daily
Pearl Index
- Method reliability: 0.3
- Application security: 9
How it works: The mini-pill contains only the progestogen hormone. This suppresses ovulation and thickens the uterine mucus.
Frequency of use: daily at the same time, no interruption
Pearl Index
- Method reliability: 0.2
- Application safety: 0.4
How it works: The T-shaped plastic body is inserted into the uterus, where it releases progestogens that thicken the uterine mucus and prevent implantation. Ovulation is not inhibited, but the hormonal activity of the ovaries is altered.
Frequency of use: Depending on the manufacturer, the hormonal IUD lasts three to five years.
Pearl Index
- Method reliability: 0.05
- Application safety: 0.05
How it works: An approx. 4cm long, soft plastic rod that is implanted under the skin on the inside of the upper arm and releases a small dose of progestogen, which prevents ovulation and thickens the uterine mucus.
Frequency of use: lasts 3 years if well tolerated
Pearl Index
- Method reliability: 0.3
- Application security: 9
How it works: The soft ring inserted into the vaginal wall releases progestogen and oestrogen evenly into the body via the mucous membrane. Like the pill, it prevents ovulation and thickens the uterine mucus.
Frequency of use: 3 weeks/1 week break
Pearl Index
- Method reliability: 0.3
- Application security: 8
How it works: A patch measuring approximately 4x4cm releases the hormones progestogen and oestrogen through the skin. This prevents ovulation.
Frequency of use: weekly
Pearl Index
- Method reliability: 0.3
- Application safety: 3
How it works: An injection of long-acting progestogen is administered every three months, which prevents ovulation and changes the lining of the uterus so that it is more difficult for sperm to pass through.
Frequency of use: every three months
Pearl Index
- Method reliability: 0.2
- Application safety: 0.2
How it works: A combination of progestogen and oestrogen is administered monthly to prevent ovulation.
Frequency of use: monthly
Barrier methods
Pearl Index
- Method security: 2
- Application safety: 18
How it works: A latex rubber is rolled over the erect penis before the penis and vagina come into contact. The rubber catches the ejaculate and prevents sperm from entering the uterus. Apart from the female condom, only the condom offers additional protection against sexually transmitted diseases.
Frequency of use: with every sexual intercourse
Pearl index
- Method security: 2
- Application safety: 12-20
How it works: The 17 cm long and 7.5 cm wide tube with elasticated rings at both ends can be inserted into the vagina up to eight hours before sexual intercourse and prevents sperm from reaching the uterus. It is the only contraceptive that enables women to actively protect themselves against the transmission of sexually transmitted diseases.
Frequency of use: with every sexual intercourse
Pearl Index
- Method security: 1
- Application safety: 20
How it works: A customised and well-fitting diaphragm reliably covers the cervix and must be inserted approximately one hour before sexual intercourse and remain in place for 8 to a maximum of 24 hours.
Frequency of use: with every sexual intercourse
Pearl Index
- Method security: –
- Application security: 7
How it works: A firm cap containing spermicide is placed on the cervix. This can be done several hours or shortly before intercourse. The cap must then remain on the cervix for at least six hours. The caps must be customised.
Frequency of use: with every sexual intercourse
Pearl Index
- Method security: 9
- Application safety: 16-32
How it works: Before sexual intercourse, a sponge is inserted into the vagina and placed in front of the cervix. It mechanically prevents sperm from entering the uterus thanks to the spermicide
Frequency of use: with every sexual intercourse
IUDs (intrauterine devices) and Co.
see above under ‘Hormonal contraception’
Pearl Index
- Method reliability: 0.6
- Application safety: 0.8
How it works: A T-shaped/chain-like/spherical plastic rod/nylon thread with copper cylinders is implanted in the uterus. The three available forms work in the same way. The copper ions inhibit sperm motility and change the lining of the uterus. This prevents fertilisation or implantation.
Frequency of use: Depending on the manufacturer and compatibility, the copper IUD lasts three to five years.
Natural family planning
Pearl Index
- Method reliability: 0.6
- Application safety: 1.8
How it works: Over the course of the cycle, cervical mucus, basal body temperature and possibly the condition of the cervix are assessed and documented. This provides an indication of the fertile days (when an additional contraceptive method is required). The method requires a thorough and careful examination of your own body. Apps, e.g. from myNFP, are available.
Frequency of use: daily, several times
Pearl Index
- Method reliability: 0.6
- Application safety: 12
How it works: Contraceptive computers monitor the symptothermal method using temperature sensors or measure the hormone levels in the morning urine. This is how the fertile days are determined.
Frequency of use: daily
Definitive contraceptive methods (sterilisation)
Pearl index
- Method reliability: 0.1
- Application safety: 0.15
How it works: The vas deferens is severed in a minor operation. This means that sperm are no longer added to the ejaculate. The hormone and sperm function of the testicles is preserved. The sperm produced are broken down by the body. The procedure does not generally impair erectile function.
Frequency of use: once
Pearl Index
- Method reliability: 0.25
- Application safety: 0.5
How it works: In a laparoscopy or during a caesarean section, the fallopian tubes are severed or tied. As a result, the sperm can no longer reach the ovaries.
Frequency of use: once
Unsafe contraceptive methods
Pearl Index
- Method security: 14
- Application safety: 35
How it works: The days of menstruation are recorded over the course of a year. This is used to calculate a probable average value for the fertile days. New apps such as Clue also use this “day counting”. Such estimates are inaccurate and are therefore not suitable for contraception.
Frequency of use: daily
Pearl Index
- Method security: –
- Application safety: 20
How it works: During sexual intercourse, the penis is pulled out of the vagina shortly before ejaculation. This method is considered unsafe, as sperm often enter the vagina through the urethra before ejaculation is felt or the penis is pulled out too late.
Frequency of use: with every sexual intercourse
Pearl Index
- Method security: 0.5
- Application safety: 2
How it works: During active breastfeeding, prolactin is released, which inhibits the activity of the ovaries. Before ovulation occurs again after the birth, no new pregnancy is possible. This works for six months – but only if you have not yet had a period, are breastfeeding fully (i.e. at least every four hours) and without additional feeds.
Application frequency: every four hours