How do you know if your egg has been fertilized during ovulation?

You can't know if an egg has been fertilized at the time of ovulation. Ovulation refers to the process in which a mature egg is released from an ovary and passes through the fallopian tube, creating the opportunity for it to be fertilized by sperm. Fertilization, the union of the egg and the sperm, does not take place at the moment of ovulation.