My 1st question is who told you that and what are they basing it off of? Your pfts? Current state of health? It has to be based on solid facts, which perhaps it might be for your situation.
Theres many many things to consider-that only you can honestly answer in your heart.
Do you have confidence in your doctor? If in fact your body can not sustain a pregnancy safely are you willing to be a mother in another way?-Adoption, etc? And its not just the pregnancy to consider, its after the pregnancy. Being pregnant is only 9 months of your life. Raising a child is many years-its wonderful!-Dont get me wrong, but the lifestyle of caring for a small baby and toddler can be more taxing on a cf mom than the actual pregnancy. It can be done successfully, as many moms here are proving, but it requires alot of planning, hard work and support. (like anything worthwhile in life)
Most docs, especially Cf docs, are good. But of course there are some out there that aren't up to date, or are just wrong. I was given bad advice from 2 docs in my life when it came to having a baby, bad advice on both ends of the spectrum. When I was engaged and 19 a doctor suggested I tie my tubes to prevent pregnancy bc I could never hope to have children period. Even though I was extremely healthy at the time.
(btw, I didn't do it, and we were very smart about preventing pregnancy)
A 2nd doctor told me 4 years later that if I wanted kids with my husband I should just go ahead and 'give my husband a baby' no matter what happened to me-And I was very sick at the time. In no shape to safely carry a pregnancy.
So 2 examples of BAD advice from doctors.
Now, I am more healthy, I work extremely hard to stick to my health routine, whereas I did not when I was younger. I'm a stay at home mom. We planned it out, didn't rush into anything, and worked very hard for many years to safely go into a pregnancy. All women with Cf are different. You need more information before deciding anything.