If you have sex during ovulation and a fertilized egg is formed, implantation usually occurs about 8-10 days after fertilization. The egg cell will survive in the body for 12-24 hours after ovulation and the fertilization ability of the sperm to unite with the egg cell is 1-2 days. When a woman has sexual intercourse after ovulation, the egg and sperm unite in the abdomen of the fallopian tube to form a fertilized egg. The gradual peristaltic movement of the fallopian tube can transport the fertilized egg to the uterine cavity for implantation and gradual development, a process that takes about 1 week. Therefore, if conception is successful after ovulation, the fertilized egg will usually come to term 8-10 days after fertilization. A woman can test for pregnancy by using an early pregnancy test 3-4 days after fertilization; a small gestational sac can be detected by gynecologic ultrasound when the fertilized egg is about 20-30 days old. In addition, in most cases, there are no obvious symptoms of fertilized egg implantation. A few pregnant women may experience a small amount of vaginal bleeding, which is not necessary to be nervous or to be treated at this time.