V.
L.,
We have a very similar situation with our daughter Julia who is currently 20 months old. She was born IUGR (she only weighed 4lbs/7oz)and has microcephaly (a small head). She has similar delays as your daughter. Julia also has all the various therapies. We have gone to numerous specialists, had a MRI done, had blood tests done, etc. and noone has been able to explain why this occurred as well as what we can expect from Julia in the future. It is very frustrating for us since we are the ultimate planners and this is something we can't really plan for well. All I can say is the most important thing to focus on is the therapies. It is something concrete you can focus on with your daughter. I have heard many stories from parents that starting early with the therapies really helped their children.
Believe me I know how frustrating all of this is but focusing on concrete things I can do for my daughter has helped us (a little bit).
All the best to you.
V.