The accused is set to be sentenced on Jan 24.
The Straits Times understands that the girl has been given a conditional warning for her role in the case.
The court heard that the teenagers were secondary school classmates and began a romantic relationship in May 2020.
The boy, now 18, would have sex with his girlfriend in his bedroom, which he shared with his brother, when the latter was not home.
Deputy Public Prosecutor (DPP) Gan Ee Kiat said the accused did not use condoms as he found it difficult to buy them because of his age.
In January 2021, the girl suspected that she was pregnant as she felt nauseous and had missed her period. The boy then bought a pregnancy test kit online for her.
After finding out about the pregnancy, the couple tried to abort the foetus on their own, but their various attempts failed.
On June 10, 2021, the girl experienced labour pains and gave birth to their stillborn son alone in her bedroom, with her boyfriend on video call.
She cut the umbilical cord with a pair of scissors. The accused then told her to cut the placenta into small pieces, flush them away and bury the body.
The girl wrapped the body in newspaper and hid it in her cabinet, but her boyfriend told her that it was inappropriate and risky to keep it in the house.
Two days later, she buried the body in the garden of her home and would sit there to grieve from time to time.