I have not had your experience, but one of my clients has. She had extensive spinal surgery as a teenager with a Harrington procedure, and revision surgery several years later. She was able to have a successful pregnancy without complication, and a normal delivery - no c-section.
Of course everyone is different, and it will be important to be followed by medical doctors who are familiar with your particular situation.
Best of luck with your pregnancy!
Nora
T-6 to L-4 Zeilke/CD (Anterior/Posterior) procedures done at age 39in 1988 at Columbia Presbyterian Hospital by Dr. Jean Pierre Farcy.