During the early stages of my pregnancy, my insulin doses practically doubled. Its the change in your hormones which will be causing problems.
As your pregnancy progresses, you will constantly need to change doses of both Lantus and Novorapid as your hormones are always changing.
Check your bgl every 2hrs, even through the night (a pain in the bum, or rather finger!!) But you will get a better understanding of whats happening. Make sure the slightest change is noted as things can change almost over night.
Good luck & congratulations on the pregnancy