Reduced hours for pregnancy in California

Has anyone been able to file for reduced hours for pregnancy disability with their employer? If so how did you go about it? I live in California where we get 8 weeks of paid family leave through EDD, but I want to decrease my hours before I use that. I was wondering if it would make sense to either just ask my job to move me to part time or officially go through my doctor and get them to sign off on pregnancy disability leave which can be used to reduce hours.