It is generally impossible to judge for yourself whether sperm enters the uterus or not. The sperm usually meets the egg in the fallopian tube and unites to become a fertilized egg before it can enter the uterus, where it can produce a chance of conception. Normally, semen enters the posterior curvature of the vagina and after a few minutes some of the sperm can enter the cervical canal and move upward, while the sperm left in the vagina encounter acidic vaginal secretions and lose their motility and die. Usually, during ovulation, the cervical mucus is thin, alkaline and nutritious, which facilitates the penetration of sperm and their movement towards the uterine cavity and the fallopian tubes on both sides. The sperm and egg meet in the abdomen of the fallopian tubes and unite to become a fertilized egg, also known as a gestational egg. The fertilized egg gradually moves towards the uterine cavity while dividing and developing, reaching the uterine cavity in about 4-5 days and then implanting in the endometrium in 6-7 days, which means successful conception. However, fertilization failure can also occur and is usually related to poor sperm or egg quality, abnormal ovarian function, endocrine disorders, and other factors. It is recommended that couples develop good lifestyle habits, pay attention to personal hygiene and avoid smoking and alcohol during pregnancy preparation, which usually helps to increase the probability of conception.