"The consequences of shaking and striking babies is well known... Regrettably in New Zealand such offending and the tragic outcome of it is all too common.
"Young and defenceless infants or children are killed by young and inadequate parents who do not have sufficient skills or maturity to enable them to cope with the responsibilities and demands of parenthood.
"This was despite there being resources and support available in such cases," Justice Venning said.
He noted Paea was assessed as having a serious personality disorder triggered by severe abuse as a child.
He also noted her guilty plea, immaturity, sorrow and remorse. While she had appeared in court before, this was a one-off incident.
A summary of facts illuminated the judge's comments.
On December 1, 2014, Paea, then 18, was at home alone with baby Milton. Her partner had gone to spend the day with his brother.
Other family members had just left after a three-hour visit.
After the family left, baby Milton woke unsettled and started crying.
Paea, who wanted to go outside for a cigarette, grew stressed. She picked up Milton holding him in her arms and began forcibly rocking and shaking him.
She continued doing so for about two minutes until he stopped crying. She put him in back in his sleeping pod but a short time later he started crying again, which made her angry.
She rocked and shook him side to side forcefully yelling at him to "shut up" and "stop fucking crying".
At some point he stopped crying, she put him back in his pod, and went outside for a cigarette.
When she went back into the house, Milton was crying again. That too was answered by Paea with forcible shaking and rocking.
Milton did not cry again for three hours.
When he woke, Paea tried to give him a bottle but she noticed he was not swallowing the milk and was pushing it back out of his mouth with his tongue.
Paea laid down with Milton on a mattress in the lounge and watched television.
Later that evening, she attempted to give him the rest of his bottle before putting him down to sleep for the night on an armchair.
Her partner arrived home and after having something to eat, the pair went to sleep on the lounge room mattress.
Between 1am and 2am on December 2, Paea's partner tried to give Milton a bottle after waking to him crying.
Milton drank only about 30mls before closing his eyes again.
At 6am Paea's partner realised Milton was not breathing after waking to the sound of him gurgling.
Paea remained asleep while her partner tried to perform CPR.
Milton failed to start breathing and after putting him in his car seat, Paea's partner ran next door asking a neighbour to take them to hospital.
Paea was woken and went to the hospital with her partner and Milton.
On arrival, staff noted Milton's pupils were fixed and dilated and had bruising to his face.
He died at about 10.30am.
A post-mortem examination showed he died as a result of a serious head injury due to Paea's rocking and shaking of him the previous day.
It was also established there was facial bruising and haemorrhages within both of Milton's optic nerve sheaths and retina.
When spoken to Paea told police, she was stressed out and frustrated by the baby's crying and that she could not control herself.
- Gisborne Herald