A ballot initiative that would define a fertilized egg as a person is “clearly unconstitutional,” the Oklahoma Sup­reme Court has held.

In an April 30 decision, the justices unanimously rejected the initiative, which will now be prohibited from appearing on ballots in November (In re Initiative Petition No. 395, State Question No. 761). The Oklahoma court said the U.S. Supreme Court “has spoken on this issue,” citing the justices’ 1992 ruling barring states from placing an “undue burden” on women seeking abortions.

The initiative would have made abortion illegal, along with most forms of contraception and some fertility treatments.

Nancy Northup, president and CEO of the Center for Reproductive Rights, one of the groups that sued over the initiative, said in a statement, “In this case, the Oklahoma Constitution said it best: It is not acceptable to propose amendments that are ‘repugnant to the Constitution of the United States.’”

The defeat in Oklahoma is the latest in a series of losses for the Colorado-based group Personhood USA, which has been drafting these amendments in the hope of getting them passed in several states. Other states that have rejected “personhood” laws recently include Mississippi and Virginia.

Nonetheless, Personhood USA is pushing ballot initiatives in Ohio, Florida, Montana, Oregon, California and Nevada, as well as a bill in Arizona. The organization has also said it may try again in Mississippi.