I was on TPN when I was pregnant with my son (about 6 years ago) and it worked wonders! 7 months into the pregnancy I was 10 lbs less than my starting weight...so my doctor decided to put me on TPN. I gained 20 lbs in 2 months! It worked really well! Although I don't have CFRD....but they really monitor your labs when you have TPN-I had to have blood taken every week, they would check my vitamin levels, etc...and formulate the TPN for that week based on what my body needed. It really was amazing. My TPN was administered through my PICC line and it took 12 hours, we would start it at 7pm and be done at 7am. I was on it for 2 months and had no liver problems.