Hi, My mother had two children after a tummy tuck. I'm not sure why its taking you long to concieve, but I don't believe its the tummy tuck. It's taking me long to concieve too, I have been trying for a year and no luck. but for me the problem is with my husband he has slow sperm motility. It's not too low but still low. I suggest you go to your doctor and speak to him/her.
Good luck and may god bless you with a child soon.