It takes about 24 hours for the sperm to unite with the egg, but it also depends on the individual differences between the two parties. After coitus, the viable sperm of the male relies on the tail to swing forward, the peristaltic movement of the muscle layer of the fallopian tube, the swing of the mucous membrane cilia and the flow of tubal fluid secreted by the mucous cells, resulting in the sperm running from the uterine cavity to the tubal peritoneum. Waiting in the tubal potbelly to combine with the egg, the sperm reaches the tubal potbelly from the vagina as fast as a few minutes, as slow as 4-6 hours, and as fast as about 1-1.5 hours. After the egg is discharged in the ovary, the egg is picked up through the umbrella of the fallopian tube and the sperm in the pot-bellied part of the fallopian tube combines with the sperm in the pot-bellied part of the fallopian tube and then swims in the direction of the uterine cavity, which takes 24 hours, and after 24 hours, if you don’t wait for the sperm, the egg will be dead, and you will have to wait for the next ovulation, and it is recommended that you pay attention to your personal hygiene during sex.