If you have already ovulated, you will still get pregnant if you have intercourse for more than 24 hours, mainly because the survival time of the egg is about 24 hours, after intercourse, the sperm will reach the fallopian tube in one and a half hours at the earliest, and will unite with the waiting egg to form a fertilized egg, and you will get pregnant. If you have ovulated, you will still get pregnant. If you are planning to get pregnant, you can choose to have intercourse after you know you are ovulating and rest in bed for at least an hour afterwards to improve your chances of getting pregnant. If you are not planning to get pregnant, you should not have intercourse, or you can have intercourse and use condoms during sex to avoid the possibility of pregnancy.