Hi,
A lot of people have trouble Levemir not lasting a 24 hour period, hence why they split the dose, which could be a option for you. It may also be possible that you need to increase the dose slightly by 1-2 units to see if this resolves the problem of increasing bg's between mealtimes. So, if you are sure that you are using the correct amount of novorapid to cover your carbs at each meal, then it certainly is the Levemir.
As you are pregnant, and pregnancy can effect diabetes control sometimes, I would discuss this matter with your diabetes nurse before making any changes, but in the mean time record all your insulin doses, carbs eaten and blood glucose readings so that the nurse can analyse these at the appointment.
Good luck!
Nigel