Amy
The ob and the hospital will keep seperate and different notes depending on your treatment.
However the hospital should have all theatre notes, anaesthetic notes (which will show what drugs in what dosages were given) and correspondence regarding your stay whilst in hospital .
All outpatient documentation would be through your ob if you saw them outside this admission.

Like Nic said, call the hospital and yes you will need to summit forms and it can take a while to get the information but you have a right to see it all. It is all legal documentation that needs to be written and kept in your file.

Hope all goes well..

PM