Sonia Blanchette faces three counts of first-degree murder as the next step in her criminal case begins today.
Her three children — Lorelie, age 5, Loic, 4, and Anais, 2 — were found dead in their mother's apartment on Dec. 2, 2012.
Last January, a judge ruled that Blanchette was fit to stand trial after she underwent a psychiatric evaluation.
The coroner ruled the two youngest children drowned while the oldest child was killed by a combination of strangling and drowning.
Toxicology reports reveal none of the children had drugs in their system.
A preliminary hearing is for a judge to determine whether there is enough evidence to send the case to trial.
The hearing is under a publication ban.