The state Supreme Court is expected to rule Wednesday in the case of a woman identified in court documents as "A.L."
The baby boy was born in September 2007. His mother denied using cocaine while pregnant and said she ingested it two days earlier when a bag of cocaine held by a friend spilled on her.
She also blamed a positive marijuana test on secondhand smoke.
A judge ordered the baby and a sibling to be cared for by the state, and an appeals court agreed in 2011.
The woman has argued that a fetus' exposure to cocaine in utero isn't a recognized harm under relevant New Jersey law.