If you use condoms correctly, you will not get pregnant, but if you use condoms incorrectly, you will not use condoms during sex, but only when you are about to ejaculate, which may lead to pregnancy; secondly, you do not check if the condom is expired before using it. Once the elasticity of the condom has expired, the condom will be broken and the semen will flow into the vagina, which will also lead to pregnancy; thirdly, the condom will slip off when using the condom, because the condom is not worn to the root of the penis, or the size of the condom is too large compared to the penis, and the semen will flow into the vagina after slipping off, which will also lead to pregnancy.