A federal judge has declared unconstitutional Michigan's law aimed at banning partial-birth abortion.

In a ruling dated Monday, U.S. District Court Judge Denise Page Hood (search) in Detroit ruled the law places an "undue burden" on women's right to choose an abortion. The parties in the lawsuit learned of the ruling Wednesday.

Hood also said the law is confusing and vague, and its exceptions for the health or life of the 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."

Previous attempts by state lawmakers to stop the abortion procedure were struck down by federal courts in 1997 and 2001.

The Michigan Catholic Conference (search) said it disagrees with the judge's ruling and will urge Attorney General Mike Cox (search) to appeal.

"The fight to end heinous partial-birth abortions will continue," Michigan Catholic Conference spokesman Dave Maluchnik said.

Doctors label the procedure "intact dilation and extraction," or D&X. During the procedure, generally performed in the second trimester, a fetus is partially removed from the womb and the skull punctured. Some doctors say it is the safest option for women in some circumstances.

The state Legislature approved a new law attempting to ban the procedure in June 2004. Hundreds of thousands of voters signed petitions that allowed the bill to become law with only the approval of the House and Senate — both of which are controlled by Republicans — after Democratic Gov. Jennifer Granholm vetoed it.

Although similar laws have been struck down, anti-abortion advocates tried a new approach with the latest ban.

Rather than name the procedure specifically, the law defined birth as the moment any portion of the fetus emerges from a woman's body. The fetus then would be a legally born person. A doctor could not do D&X unless it was necessary to save the mother's life or to avoid an "imminent threat" to her physical health.