It seems to be more common to conceive naturally with blocked tubes after you have had a pregnancy. I think the hormones of pregnancy can help relax the tubes and that can unblock them if they can release what is blocking them. When they are blocked from damage from adhesions and endo the chances of them become opened enough to get pregnant naturally are reduced. But if you have a healthy looking blocked tube/s with no adhesions then I'd say the chance is much better.
Ninah did you have ICSI because of sperm issues also?
In a few months we will be starting IVF for a damaged tube which is open but the outside is in poor condition (other lost from ectopic pregnancy) I am IVF is successful and then we have a natural surprise down the track also as we wouldn't be having IVF again once we birth a baby.