Condoms can fail to prevent pregnancy when they are

• Not used correctly
• Used inconsistently
• Broken during sex
• Manufactured improperly
• Damaged after manufacture Expired

Approximately 2 - 5 percent of condoms tear during use. The majority of these failures are caused by human error, which can include not using enough lube and creating microscopic tears with rings or long, sharp, or jagged fingernails, among other possibilities. Incorrect use includes unrolling a condom backwards, not unrolling condom to base of penis, not leaving a half-inch of empty space at tip of condom, and not holding the rim of condom down along base of penis when removing penis after ejaculation. Inconsistent condom use means not using a condom every time you have sex, or not putting condom on soon enough -- such as right before ejaculation instead of at beginning of intercourse -- before penis comes in contact with your partner's genitals. Any risk of pregnancy resulting from pre-cum on fingers being transferred to a condom is unlikely. To be extra safe, a man could put on a condom at very beginning of sexual play, rather than wait until you're ready for penetration. Condom failure may also be more likely if either of you have pierced genitals. If condoms break when used correctly, tear is most likely due to hidden weaknesses in rubber. These weaknesses may get past manufacturing regulation as some tests administered for strength and leaks are used to spot check a batch of condoms as opposed to testing each individual condom.