So now it looks like I have to switch doctors

When I started with this new OB ( I moved out of state earlier this year so I needed a new Dr.) I asked what hospitals they deliver at. They work at one that is close to my job but this is not where I want to deliver. I want to deliver at a hospital equal distance from home and work, which is about 15-20 minutes from their office. They told me they deliver at both hospitals. Now at my appointment yesterday the doctor tells me that it is not convienant for her to deliver at the other hospital and said that if I want to deliver there, she will recommend another doctor for me. Why didn't they say this 20 weeks ago Has anyone done this? Is your health care effected? Thanks