Hi Alisha,
From my own experience, I did not have any lung issues during my pregnancy and was not induced early because of CF. Although, I was induced due to me having a pregnancy rash (PUPP). It was so horribly itchy I couldn't stand it anymore so they said I could be induced at 39 weeks. My baby grew perfectly normally and was 8 lbs 6 oz at birth. However, I did have frequent ultrasands to check growth (since they assumed babies of CF moms were small) but he was always in the upper range (90th percentile) for weight thorughout the pregnancy. I did not gain much weight during pregnancy though (only 12 lbs), but I was a little on the chubbier side prior to getting pregnant anyways. I did lose about 30 lbs after giving birth, so it was a good thing I had that extra weight because I got quite thin at that point. I also had frequent ultrasounds and NSTs due to the cord being wrapped around his neck a couple times, but by the time he was born it had unwrapped completely. So I really just endured "normal" pregnancy complications and nothing happened because of my CF. But that's just my experience. I think some CF women have to deliver early because of complications, frequent infections, difficulties gaining weight, etc.
Good luck!