The sperm and the egg unite in the abdomen of the fallopian tube. If it happens to be the time of ovulation, during which intercourse takes place, the sperm can pass through the cervical canal to the uterine cavity, from there to the interstitial part of the fallopian tube, and then to the isthmus of the fallopian tube, where they will be fertilized after uniting with the egg waiting in the abdomen of the fallopian tube. Most of the fertilization process is completed in a few hours or less, and at the latest in less than a day. On the seventh day after fertilization, a blood test will reveal a rise in HCG, which will determine if the egg is pregnant.