Depending on the category, the injury in the infant may not be apparent at first. Mechanical injuries usually involve a physical touching of the infant's body. For example, the doctor or midwife might tug on the infant's arm during the birthing process. Another example of mechanical trauma would be injury to the infant's skull during birth. This trauma could cause subsequent damage to the brain of the infant.
Anoxic injury refers to injury to the brain as a result of decreased oxygen supply.
It is important to pay attention to what is going on during the entire pregnancy, up to and beyond birth of the baby. Even a small detail can be important in explaining why your baby has a problem. The reason for a traumatic brain injury may not be obvious at first. Details during the pregnancy and delivery can be very important and relevant. You are correct in that the entire process seems overwhelming.