Generally speaking, there is a high probability of pregnancy when ovulation occurs the day after sex. Sperm enters the female vagina and has a maximum survival time of 72 hours; while ovulation is not a fixed period of time, it may be lengthened or shortened by hormone levels and other influences, so the first five days and the last four days belong to the ovulation period. Therefore, the possibility of pregnancy cannot be ruled out. If you don’t want to get pregnant accidentally, and the intercourse is not more than 72 hours, you can take emergency contraceptive pills to remedy the situation. You can also see if there is a delay in your next period and use a pregnancy test to confirm whether you are pregnant.