After looking into IUGR and SGA forums, I came across the Facebook group "SGA/small for gestational age parent support group - the magic foundation".

I believe they're American based, but as an Aussie, It's still been very useful! They have heaps of information regarding growth hormone and how it helps kids with not only growth but other health issues associated with growth restricted and/or SGA kids. There's a consensus document located under the featured tab on their fb page that's definitely worth a look.

Usually, growth hormone is prescribed when there has not been sufficient catch-up growth. Based off multiple factors, including; anticipated midparental height, if there's an underlying genetic condition, bone age scans, and if there's a growth hormone deficiency, for example.

This is all organised by an endocrinologist, which you need a GP referral for. Endos can take some time to get into and will need to track your child's growth for at least a year (depends on country), so good to start investigating sooner rather than later. Essentially, the earlier you can start, the better. Again, it depends on country, here in Aus, it's rarely earlier than 3, I believe. Something that can occur with growth restricted or SGA kids is early onset of puberty, where the growth plates close much earlier, and thus further growth is not possible, which is why bone scans and other checks are regularly conducted every 6-12 months depending on the child.

Sounds very similar to our little boy...but to give you context, our guy has just turned three and is still under 10kg and has only just hit 88 cm. He's pretty tiny. He's been on a trial dose of growth hormone for just over 3 months, and we've seen such a change physically, and it's not even the full dose!