I am asked it a lot, "has Joseph caught up?" I always feel like saying "to whom?" I find "catch up" a really difficult concept to define, and I really dislike that term, and think we can come up with something better.
There are two basic elements to catch up in my opinion, and the first is growth. This is somewhat easier for me to define and answer. When Joseph was born he was on the 0.4th centile on the newborn charts, and dropped right off and followed his own line. At first his growth was very slow, and there were some concerns about it. Then at about six months, he took off, climbing the charts quicker than Cher Lloyd with Simon Cowell behind her. He then settled on the 25th centile happily, and that is where he has stayed, growing slowly but surely.
So in a sense he has "caught up" in terms of growth, although in clothes he is still in 12-18 bottoms with 18-24 tops, he is nowhere near 2-3 clothes yet, but that's ok, many term boys of his age are the same.
Developmental catch up is a lot more complex in my mind, because there is so much variance. Joseph is a chatterbox and everyone comments on his amazing speech. But, when you compare him to children born at the same time as him, some of them are speaking in whole sentences, where Joseph is still doing two word pairs with the occasional three word sentence. However the little boy next door, six months older, only has about 20 single words.
Joseph, as I have well documented, took an age to walk. He was 23 and half months before he could walk independently, and even now he is still quite behind, he can walk, but not for very long and I am still reliant on a pushchair to some extent. He also is a terrible listener and if he gets the inclination, will just bolt. However to see him walk, climb, paddle and run you really wouldn't think that he had struggled with this. I only notice he is a bit behind because I am with him every day, and occasionally compare him to others.
I prefer, rather than catch up, to think of it as "gap closure", closing the gap between those born prematurely and those born at term. I think that's a much more positive term than "catch up" and doesn't imply that they were "behind" in the first place, just that there is a gap between the age that they were born at, and the age they were meant to be born at. At some point there will come a day where there is no gap, just a normal variance in ability and interest.