Iowa’s six-week abortion ban is set to take effect on Monday morning, changing the map of abortion access in the Midwest and giving Republicans in the state a long-sought policy victory.

Since the Iowa Supreme Court ruled 4-to-3 last month that the ban could be enforced, it had mostly been a matter of when, not if, the law would take effect. Last week, a state district judge said an injunction blocking enforcement of the ban would be dissolved at 8 a.m. local time on Monday. Until then, abortion had been legal in Iowa up until about 22 weeks of pregnancy.

The new Iowa law highlighted the divergence of state-level policies since the U.S. Supreme Court overturned Roe v. Wade, ending the national right to abortion in 2022. While some Midwestern states, including Illinois and Minnesota, which are governed by Democrats, have moved to maintain or expand abortion rights, sweeping bans have taken effect in others, including Missouri and South Dakota, which are led by Republicans.

The Iowa law, passed by Republicans in a special session last year and signed into law by Gov. Kim Reynolds, a Republican, allows abortions until the point where there is what the legislation calls “detectable fetal heartbeat,” a term that medical groups dispute. The law assumes that this is roughly six weeks of pregnancy, before many women know they are pregnant.

The Iowa legislation includes exceptions for rape or incest, when the mother’s life is in serious danger or she faces a risk of certain permanent injuries, or when fetal abnormalities “incompatible with life” are present.

When it was announced that the ban would take effect on Monday, Ms. Reynolds called it “a victory for life.”

“There is nothing more sacred and no cause more worthy than protecting innocent unborn lives,” she said in a statement.

Officials with Planned Parenthood said in a statement that they would comply with the new law, and would be “prepared to help patients determine whether they can still be seen in Iowa or must travel to different health centers in Minnesota, Nebraska and other neighboring states.”

Democrats, who have seen their political power in Iowa dwindle, called the State Supreme Court ruling dangerous. “Activist judges and anti-choice Republicans cannot be allowed to control Iowans’ lives,” Pam Jochum, the State Senate’s Democratic leader, said last month.

Democrats hope to use support for abortion rights to their electoral advantage this year in Iowa and beyond. A Des Moines Register/Mediacom Iowa poll from last year found that 61 percent of adults in the state believed abortion should be legal in most or all cases, while 35 percent believed it should be illegal in most or all cases.

Though former President Donald J. Trump is widely expected to carry Iowa this year, as he did in 2016 and 2020, Democrats hope to flip at least one congressional seat in the state and reduce the size of the Republican majorities in the Iowa Legislature.