This is a big problem - continuity of care is a big part of birth and this is why the Maternity Coalition are fighting for it. Shiftwork and unknown carers are not good for a birthing mother. Yes you can get an Ob, but they are not there for the birth and wont hold your hand and get you through birth - they are not ideal birthing partners. You might like to considers your own private midwife or doula Studies say (including a report in the Cochrane Library) that birth goes much better with continuous care IDEALLY with someone who is not a staff member of the hospital. You can get a great midwife like yourself and go really well, but things change and it's hard leaving it up to chance that you will get a midwife you will click with for your whole birth.