Abortion-rights groups say they have filed a lawsuit challenging the constitutionality of the nation's most restrictive abortion law, which bans most abortions once a fetal heartbeat is detected, around the sixth week of pregnancy.

The Iowa law is slated to take effect July 1. Planned Parenthood and the American Civil Liberties Union filed the challenge Tuesday in Des Moines. The groups are seeking an injunction that would put the law on hold during the lawsuit, a process that could take years.

The Iowa attorney general announced that he would not defend the law because it would undermine rights and protections for women.

Republicans want the legal challenge to reach the U.S. Supreme Court in hopes of overturning the 1973 Roe v. Wade ruling.