An autopsy found that the boy weighted only 9.7 kilogrammes at the time of his death in 2022, more than 4 kilogrammes lighter than when he was two.
Autopsy findings showed all of his organs and muscles had atrophied, suggesting that he had suffered from prolonged starvation.
The court also heard that the boy was repeatedly confined and caned by his mother, with a total of 129 injury marks still visible across his body at the time of the autopsy.
In sentencing, High Court judge Susana D’Almada Remedios described the case as “horrid, devastating, heart breaking and tragic”, saying the boy had suffered extreme cruelty over a lengthy period of time.
The judge called the defendant’s act of starving the boy to death as a “protracted, cold-blooded annihilation carried out with the patience of a torturer.”
She added that the mother was not driven by a flash of rage, but that her actions had “exposed a savage nature utterly devoid of the empathy inherent to motherhood.”
The judge pointed out that social workers had repeatedly conducted home visits and last saw the boy three months before his death.
She found it incomprehensible that social workers were unable to spot the boy’s abnormal weight and height, adding that his life might have been spared had anyone noticed the abnormalities.
The defendant had earlier pleaded guilty to charges of manslaughter and cruelty to a child.
She was sentenced to 20 years’ imprisonment for manslaughter and six years and four months for cruelty to a child.
Two years of the child cruelty sentence would run consecutively with the manslaughter term, bringing the total jail term to 22 years.
The defendant’s three other children have been placed in foster care.