If the condom falls off during sex, a small amount of semen will enter the vagina. If you have intercourse during ovulation, there is a chance of pregnancy, because the combination of sperm and egg during ovulation will be pregnant, but no egg is discharged during the safe period, which is not pregnant, so whether the condom falls off or not, it is related to the time of intercourse. If the condom falls off during ovulation, it is recommended to take emergency contraceptive pills, such as Yutin and other drugs, preferably within 72 hours after intercourse, which can play a contraceptive role, but if you have intercourse during the safe period, which will not be pregnant and do not need to take birth control pills. When you have sex, you need to choose the right condom, if the condom is too big or too small, it will cause the condom to fall off and lead to contraceptive failure, you also need to choose the regular manufacturer of condoms, if the quality of the condom is not good, broken, etc. will also cause contraceptive failure.