(This is just my own experience and I know that everyone’s can vary, so please don’t be alarmed by my own experience - you are much further along than I was any of the times. I don’t want to worry you more than necessary.)
With my first pregnancy, I wasn’t seen by anyone until I was around 5 months in so had continued with azathioprine as normal. No flare ups during pregnancy, DD was born full term but very small and her birth was difficult (ended up being a forcep delivery). Drs suggested it could have been linked to the azathioprine but it was never confirmed.
Years later, I was trying for baby #2 and got pregnant 3 times, each one ending in miscarriage before 8 weeks. I had been advised to stop taking the azathioprine due to the risks to the baby but because the Crohns wasn’t being treated, I had flare ups each time. The fourth time (my fifth pregnancy in total), I was advised to continue with the Azathioprine despite the risks as the flare ups were causing more problems. Like DD, DS was born full term, low birth weight and a difficult birth. DS also had low blood sugar at birth so we had to stay in hospital for a while so they could monitor him, but once that picked up all was ok. They both caught up in size pretty quickly.
It’s complicated but for me, continuing the medication was for the best because, despite the difficulties at birth, they have thankfully grown up healthy with no long-term complications.