Monique Kapua appeared before the Health Practitioners Disciplinary Tribunal accused of failing to carry out standard anti-natal tests or alert the mother to the risks of a prolonged pregnancy.
The stillborn boy was delivered in 2006 when his mother's pregnancy was two to three weeks overdue.
Kapua denied any wrongdoing.
In its ruling the tribunal says Kapua's failure to undertake sufficient standard tests or to document why is a significant breach of the midwife's professional obligations.
The tribunal has called for submissions in the next two weeks on the appropriate penalty.
