These are the biological terms and the stages of fetal development:
- Zygote: an egg that has been fertilized by a sperm
- Blastocyst: a zygote that has begun to divide and grow
- Embryo: the zygote becomes an embryo around 5 weeks of pregnancy, when various systems of the body begin to form
- Fetus: around 8 weeks pregnancy, when the heart has begun beating, your baby will be considered to be a fetus
