Hi Colleen,
My doctor did a study on pregnancy and CF. From what he found, about 50% of CF women get GD when pregnant. About 50% of those continue to have CFRD after giving birth (if they didn't have CFRD prior to the pregnancy).
Prior to getting pregnant, I had a couple below-borderline fasting sugars, like around 112 or so. I was sure I would develop GD during my pregnancy.
I took an OGTT in my 32nd week of pregnancy (I think) and it was slightly high (like 135). I went through the 3-hour test and everything came out fine to my surprise.
My doctor told me that it's usually a good idea to just go right to insulin with GD because that way you don't have to worry about changing your diet around - which you don't really want to do with CF and the added stress of pregnancy.
So it's not a guarantee that you will develop GD, but I think it's about a 50/50 chance. But don't worry. Hey, look at the bright side - it will give you a chance to "practice" just in case the real thing (CFRD) comes around later in your life. At least that's how I looked at it <img src="i/expressions/face-icon-small-smile.gif" border="0">