Detroit ? A federal judge has declared unconstitutional a Michigan law that supporters said would ban a late-term abortion procedure.

In a ruling dated Monday, U.S. District Court Judge Denise Page Hood in Detroit ruled the Legal Birth Definition Act places an “undue burden” on women’s right to choose.

Hood said the law is confusing and vague, and its exceptions for the health or life of a mother are meaningless and unconstitutional.

“The act does not describe any specific procedure to be banned,” Hood wrote. “The act also does not distinguish between induced abortion and pregnancy loss.”

Parties in the lawsuit learned of the ruling late Wednesday when it was obtained by the Detroit Free Press. It was not immediately clear why the parties were not notified of the ruling.

Proponents of the law said they were attempting to ban a procedure they call “partial-birth” abortion. Previous attempts by state lawmakers to stop the abortion procedure were struck down by federal courts in 1997 and 2001.