Oliver weighed little more than a tub of butter when he was born at 24 weeks at Brisbane's Mater Hospital

Erika Brown's son Oliver was born at 24 weeks.  (Supplied: Erika Brown)

Erika Brown was still a teenager when she gave birth 16 weeks early to a baby boy, weighing little more than 500 grams.

Her son Oliver Bate-Brown was so small he could almost fit in her hand, his little legs dangling down.