Henry McMaster, the Republican governor of South Carolina, on Thursday signed into law one of the most restrictive abortion policies in the country.

The legislation bans almost all abortions after six weeks of pregnancy, which is when doctors can usually first detect cardiac activity in an embryo but before many women know they are pregnant. Doctors who perform an abortion in violation of the law face up to two years in prison.

Ladies and gentlemen, this step we take today was long in coming and monumental in consequence. But our battles are not over, McMaster said. Yet I believe that the dawn of victory is upon us.

If allowed to go into effect, the legislation could ban almost all abortions for the nearly 1 million women of reproductive age in the state, according to advocates.

The South Carolina statute is part of a wave of extreme abortion measures passed by Republican-controlled state legislatures in recent years with the express goal of triggering a lawsuit that could overturn Roe v. Wade.