GC nic ... It might be a fee structure thing ... Just to give you a different perspective ... Most OB's charge a "management fee" which INCLUDES your delivery. After you've paid your management fee appointments are at more regular intervals as well as whenever they (or you) feel necessary. To charge you a single visit fee every time you went there might become incredibly costly for you and you might not get the "value " of the fees including your delivery.
Just another point of view ... She may have been coming from a a completely different angle