Cerebellar Hypoplasia is most commonly caused by the kitten’s mother contracting the Panleukopenia virus, or being vaccinated against Panleukopenia, while pregnant. If the mother passes on the virus during the end of pregnancy, the kittens can be born with CH. It is thought that there is only an 11-day window in utero when the kittens can contract CH. Kittens with CH are not infected with or carriers of the Panleukopenia virus, it has only stunted their cerebellum’s growth while in the womb. Cerebellar Hypoplasia can also occur if a trauma, including malnutrition, occurs to the kittens while in the womb.