 Unlike any other condition that may present with similar effects, spastic diplegia is entirely congenital in origin—that is, it is almost always acquired shortly before or during a baby's birth process.Things like exposure to toxins, traumatic brain injury, encephalitis, meningitis, drowning, or suffocation do not tend to lead to spastic diplegia in particular or even cerebral palsy generally.Overall, the most common cause of spastic diplegia is Periventricular leukomalacia, more commonly known as neonatal asphyxia or infant hypoxia—a sudden in-womb shortage of oxygen-delivery through the umbilical cord.