Fetal Ossification

*Fetal ossification* is the process by which the fetus gradually becomes hard and ready for birth. This process begins approximately five months after conception and continues until the fetus is born. Fetal ossification may vary between animal species and humans, and may also occur over different periods of time.

In nature, ossification occurs every time a new offspring is born. The bones of developing placental mammals ossify in several stages, which can be divided into three main phases. The first phase occurs before birth and involves the formation of bone matrix and bone cells. The second phase lasts both during and after birth and is characterized by bone growth and then ossification. The third phase is