(CNN) - Abortion rights supporters are suing Missouri over its ban on abortions after eight weeks of pregnancy, arguing that the measure is unconstitutional.
Planned Parenthood, the American Civil Liberties Union and Paul, Weiss -- the law firm that argued in support of legalizing same-sex marriage in a landmark Supreme Court case -- filed the case in federal court in Missouri against Republican Gov. Mike Parson and other state officials on Tuesday evening.
"By imposing a ban on abortion prior to viability, the 8-Week Ban violates Plaintiffs' patients' rights to privacy and liberty guaranteed by the Fourteenth Amendment to the United States Constitution," the groups wrote.
Parson signed the Missouri measure into law in May, and it is slated to go into effect on August 28. It would penalize medical professionals who perform abortions after eight weeks into a pregnancy -- before many women know that they are pregnant -- with up to 15 years in prison. The law does not include exceptions for instances of rape or incest, only for instances of "medical emergency," such to prevent a pregnant woman's death or "substantial and irreversible physical impairment."
The law would ban abortion outright should the Supreme Court overturn Roe v. Wade, the 1973 landmark ruling legalizing abortion nationwide and establishing the age of viability at 24 weeks. It also includes bans on abortion at 14, 18 and 20 weeks, which could go into effect if a court finds the eight-week ban invalid.
In the context of Roe v. Wade, "the Bans therefore outright forbid patients from exercising their constitutionally protected right to a pre-viability abortion in Missouri, in violation of the Fourteenth Amendment to the United States Constitution," the plaintiffs wrote.
Alexis McGill Johnson, acting president and CEO of Planned Parenthood Federation of America, said in a statement that her organization "will not cower to politicians who are trying to dismantle our access to safe, legal abortion — not in Missouri, and not anywhere else."
"These dangerous and illegal bans put people's health and lives at risk," she said, adding, "We will fight to ensure that every person can still access reproductive health care: no matter what."
CNN has reached out to Parson's office for comment on the lawsuit.
Following the bill's signing in March, the governor tweeted, "By signing House Bill 126 today, we are sending a strong signal to the nation that, in Missouri, we stand for life, protect women's health, and advocate for the unborn. All life has value and is worth protecting."
This story has been updated.
CNN's Dakin Andone contributed to this report.