As I'm sure you know Cerebral Palsy
is a non-progressive, non-contagious conditions of cerebrum malfunction manifesting primarily as a motor disorder. It is caused often caused by assaults of low oxygen levels, radiation or infections while the baby is still in the uterus or while it is being born. As of today, there is no identifiable gene or inheritance pattern that has been well laid out for cerebral palsy. For this reason, it is not classified as a genetic disease. I should note that just because there hasn't been a gene or inheritance pattern well defined, it doesn't mean that genes don't play a role. Genetics plays a role (sometimes very small) in the risk for just about every disease and trait that exists. In your particular situation, there are likely no additional measures beyond what is already standard which will decrease your risk for having a baby with CP. I would suggest you schedule an appointment with the OBGYN that will be performing your prenatal care. He or she will be able to get you in touch with a geneticist
(if necessary) who can go through your family history and give you a more accurate risk assessment. Good luck.