Do Condoms Work? The Truth About Condom Effectiveness

All methods of contraception are used to prevent pregnancy, but condoms have the added advantage of providing protection against infection and the spread of sexually transmitted diseases (STDs). How effective are condoms at doing these two things? Are they really as effective as other contraceptive methods at preventing pregnancy? And since one of the most common reasons for using a condom is to provide protection against infection, are they really an effective barrier against being infected by STDs?
In this article we look at some of these questions.
Does using a condom prevent pregnancy?
Condoms are an extremely effective means of preventing pregnancy. Of course, no method of contraception is 100% effective because there will always be instances of incorrect or inconsistent use. This is as true of "the pill" or any other form of contraception as it is of condoms. However clinical studies have shown that high quality condoms, when used consistently and correctly, provide an excellent barrier against pregnancy. These trials have shown that correct and consistent use of condoms can have between 95% and 98% contraceptive efficacy rate.
How often do condoms fail?
The main reason that condoms "fail" to prevent pregnancy or infection is not because the condom itself has "failed", but because of incorrect or inconsistent use. Latex condoms can be weakened by oil-based lubricants like petroleum jelly. They can also be weakened by exposure to sunlight or by age. Sometimes they are torn by teeth or fingernails. But putting these incorrect uses aside, condoms almost ever "fail".
How often do condoms break or slip off?
In the United States, most studies of breakage caused by fault in the condom itself have shown breakage rate is less than 2 condoms out of every 100. Studies also indicate that condoms slip off the penis in about 1-5% of acts of vaginal intercourse and slip down (but not off) about 3-13% of the time. Again, these rates are influenced by the care one takes when using a condom.
Are condoms effective at preventing infection from HIV or STDs?
Studies have shown that if a latex condom is used correctly and consistently (every time you have sex), they are a highly effective barrier against infection. This has been demonstrated most clearly by studies of "discordant" couples in Europe. A "discordant" couple is one in which one partner in infected with HIV and the other one is not. In a study of 123 couples in which condoms were used consistently, none of the infected partners became infected.
Do thinner condoms give less protection against pregnancy and STDs?
Thinner condoms are equally effective as a protection against both pregnancy and infection by STDs. However they may be more easily damaged by fingernails, teeth, jewelry and other incorrect uses, so extra care should be taken when using a thinner condom.
Are all condoms thoroughly tested before being sold?
All brand name condoms are subjected to rigorous quality control tests at every stage of the manufacturing process. In the US, each condom is electronically tested for holes and defects. Samples are taken from each lot and visually examined using a water leak test. In this test the samples are filled with 300 ml of water and suspended for 3 minutes.
Samples from each lot are also subjected to an Air Inflation Test. This involves filling the test condoms with air until they reach the bursting point. They typically will hold about 40 liters of air -- the equivalent of 9 gallons of water!
Other samples are checked for size and thickness, some are tested to destruction for physical strength, and still others are prematurely aged by applying high temperatures to ensure that they will retain their quality well beyond their 5 year product life.
In all regards, condoms have been shown to be an effective way to prevent pregnancy as well as being a highly effective way of guarding oneself against HIV or STD infection.