Oh my gosh! Are you insane?!?! LOL
I have a 3.5-year-old and a 2-year-old, and I don't even know what I'd do with myself if I had another one. And oddly enough, we did consider having one more recently...but after thinking long and hard, we realized two was plenty <img src="i/expressions/face-icon-small-smile.gif" border="0"> However, I did not carry both of my children, only one, so I don't have experience carrying more than one pregnancy. But I honestly wouldn't even think of carrying more than one anyways because it really took a toll on me and my health at first. I feel fortunate that my health is back up to baseline now and I want to keep it that way.
But honestly, I do know there are CF women out there who have had more than 2 kids. Hopefully you will find the answers you are looking for.
And I think it's really great that you're thinking about extending your family - it's great that we are living longer and healthier lives so that we can live our dreams <img src="i/expressions/face-icon-small-smile.gif" border="0">