This article is about the stage of prenatal development. Views of a Foetus development of the boy in 11 months the Womb detail. A fetus is a stage in the prenatal development of viviparous organisms.
The fetal stage of human development tends to be taken as beginning at the gestational age of eleven weeks, i. A human fetus, attached to placenta, at around twelve weeks after fertilization. Until around nine weeks after fertilization, this prenatal human would have been described as an embryo. In humans, the fetal stage commences at the beginning of the ninth week. The head makes up nearly half of the fetus’ size.
At this point in development, uncontrolled movements and twitches occur as muscles, the brain, and pathways begin to develop. The amount of body fat rapidly increases. Thalamic brain connections, which mediate sensory input, form. Bones are fully developed, but are still soft and pliable. Iron, calcium, and phosphorus become more abundant. Fingernails reach the end of the fingertips. There is much variation in the growth of the human fetus.