Third week of pregnancy: fertilization and embryo development

By the end of the second week and the beginning of the third week, an egg is released into the Fallopian tubes, so that a sperm is able to reach and fertilize it. If fertilization takes place, the formation of a zygote begins, which will continue developing until the blastocyst stage.

As embryo development continues, it will begin its journey to the uterus, where it will implant by the end of the third week or beginning of the fourth approximately in order to continue growing.