At the end of the 8th week, the embryonic stage is over, and the fetal stage begins.
Animals do not routinely cull descendants past the egg or fetal stages, for example.
Even before the fetal stage begins, a six-week-old human embryo can arch its back and neck.
In humans, the fetal stage commences at the beginning of the ninth week.
Blood samples are taken while the infant is still in the late fetal stage.
This period is described by various sources as lasting through the second or third month of pregnancy, when the fetal stage begins.
The fetal stage is 8 weeks until birth.
A fetal stage means that young are more developed when they are born.
Many vertebrates have fetal stages, ranging from most mammals to many fish.
The prevalence of convergent evolution to the fetal stage shows that it is relatively easy to develop.