What are the symptoms of an embryo already forming?

Embryo formation is the process by which a fertilized egg develops into a multicellular organism. The symptoms of an embryo already forming can vary depending on the stage of development. In the first few days after fertilization, there may not be any noticeable symptoms. However, as the embryo implants in the uterus, some women may experience light spotting or cramping. This is implantation.