If you wear a condom, you will not get pregnant in most cases, and you may get pregnant in very few cases. For example, before having a roommate, if you do not carefully check whether the condom is within the validity period, check whether there is damage, etc. If you use an expired condom or use a damaged or leaky condom when having sex, it is more likely to cause contraceptive failure. Secondly, some people do not wear condoms all the time, but only use condoms in the middle of the same room. For example, if you wear a condom when you are about to ejaculate, it is more likely to cause contraceptive failure and lead to unexpected pregnancy.