Smart Doctor on Instagram‎: "✨ In which week can the fetus move its limbs? | Fetal Development 💞 . . Fetal development is a fascinating process that occurs in three main stages: germinal, embryonic, and fetal. Here’s a brief overview of each stage: 1. Germinal Stage (Weeks 1-2) Fertilization: The sperm and egg unite to form a zygote. Cell Division: The zygote undergoes rapid cell division as it travels down the fallopian tube. Implantation: The blastocyst implants itself into the uterine wall.