In the four and a half decades since the Supreme Court legalized abortion in the landmark case, Roe v. Wade, it has fallen to state legislatures to pass laws designed to limit abortion.

Now, with state legislatures around the country gathering for their 2018 legislative sessions, experts on both sides of the abortion debate expect policymakers will continue to chip away at Roe v. Wade, even as some state policies are weaving their way through the courts.

“It’s really the panoply of restrictions pulled together that makes access to abortion so difficult, and it’s different for every state,” said Elizabeth Nash, senior state issues manager for the Guttmacher Institute. “But looking back over 45 years, it’s been state policy that’s been the detriment for access in the states.”

Since the high court’s 1973 ruling, states have enacted 1,193 laws placing restrictions on abortion, with 34 percent of those laws being passed in the last seven years alone, according to an analysis from the institute.

In the decade after the ruling in Roe, states adopted 380 new laws restricting abortion. These ranged from limiting abortions taking place later in a woman’s pregnancy, to requiring minors to obtain parental consent.

From 1983 to 2010, states enacted another 406 laws restricting abortion access. These, the institute found, centered on requiring women to undergo counseling, implementing waiting periods, and limiting partial-birth abortion.

But both opponents and supporters of abortion rights point to 2010, and the legislative sessions in 2011, as key milestones in the abortion debate. That's because the elections that year brought a wave of conservative lawmakers into state and federal legislatures.

“2011 was a turning point,” Nash said. “You can’t have 1/3 of abortion restrictions enacted without that being an important piece of the story. What it does highlight is the importance of state legislatures and state policy with regard to abortion, because it has been primarily policies at the state level that determine access, not federal policies.”

Indeed, in 2011, state legislatures passed 92 laws restricting abortions, more than in any previous year. From 2011 to 2015, state legislatures adopted an average of 57 new laws each year placing limits on abortion, according to Guttmacher.

“When Republicans came in, you did see a great uptick in state regulation on abortion,” said Sue Swayze Liebel, coordinator of the National Pro-Life Women’s Caucus for the Susan B. Anthony List. “As state houses start to turn and get more Republican-controlled, the ability to enhance regulations to meet today’s medical marketplace standard is happening.”

Liebel said that over the past eight to 10 years, lawmakers at the state level have been working to enact laws that place additional regulations on abortion clinics, as well as informed-consent provisions.

But the rise of technology has also given way to new laws, particularly surrounding ultrasounds.

In three states, abortion providers are required to perform an ultrasound on women seeking an abortion, and are mandated under state law to show and describe the ultrasound image. Similar policies in Kentucky, North Carolina, and Oklahoma are being challenged in the courts.

Meanwhile, nine states that require an ultrasound to be performed require the abortion provider to give women the opportunity to view the ultrasound image, according to Guttmacher.

“Now that we have 3D and now 4D, it’s so much more clear that that is a baby and not a blob of tissue," Liebel said.

Perhaps most prevalent in the states, though, is legislation banning abortions 20 weeks after fertilization.

Eighteen states have enacted 20-week abortion bans; Iowa and Kentucky were the latest to do so in 2017.

Liebel believes the 20-week ban has done the most to chip away at Roe in the 45 years since the Supreme Court’s ruling. But abortion rights advocates say the policies are unconstitutional.

Most recently, in 2017, 19 states passed 63 new laws limiting abortion, the highest number of restrictions in a single year since 2013, according to Guttmacher.

These new policies trended toward banning some types of abortion, as well as those that occur under specific circumstances, such as 20-week abortion bans, prohibitions on dilation and evacuation abortions, and bans on abortions conducted in cases of sex or genetic anomaly, such as Down Syndrome.

Dilation and evacuation is a procedure typically used after the first 12 weeks of pregnancy, and the anti-abortion community calls the prohibition of this procedure a “dismemberment ban.”

Expanding access

Although 2017 saw another uptick in abortion restrictions from the states, a wave of new laws from states expanded access to abortion.

In New York, for example, state lawmakers required abortions to be covered by private health insurance plans. Oregon did the same.

Delaware, meanwhile, passed a law establishing a framework for abortion access in the state.

“You saw the states moving in two directions,” Nash said. “You saw 63 abortion restrictions enacted in 19 states, and some states moving to protect and expand access.”

These diverging actions, she said, can be attributed in part to the election of Donald Trump and the fact that both houses of Congress are GOP-controlled.

“I see two motivations behind the pushback against restrictions,” Nash said. “One is that people had seen the restrictions pass in other states and didn’t want it to come to their state. And it is a reaction to what’s happening federally [with Trump's presidency].”

“For the first time in a number of years, abortion rights are under real threat at the federal level. States may be motivated because of that to protect access,” she continued.

Lawmakers have already begun their 2018 legislative session, and experts predict more states will take up legislation limiting abortions for sex selection, race, or disability, as well as on the use of dilation and evacuation.

Eight states have passed legislation banning dilation and evacuation abortion, but the laws have only been enacted in two states: Mississippi and West Virginia. In the other six, courts have intervened and blocked the policies either permanently or pending a final ruling.

Nash doesn’t believe the intervention from the courts will slow states down.

“I don’t think states are waiting to see what comes from the courts,” she said. “It’s a trend that’s been building, and it’s not necessarily clear where it will go.”

Eight states have bans preventing abortions for sex selection. One state, Arizona, prohibits abortion because of race, and North Dakota bars abortion in case of genetic abnormalities.

“A couple of states went first and are testing that out and seeing how that works in their legislatures, and a few more are going to be introducing it,” Liebel said of laws banning abortion for reasons of sex, race, or genetic anomaly.

States have already played the primary role in passing laws that place limitations on abortion in the wake of Roe v. Wade, and neither Liebel nor Nash believes the trend will reverse in 2018.

But with Trump in the White House, the anti-abortion community is hoping to see the president nominate justices to the Supreme Court who will finally reverse the 1973 ruling.

If that were to happen, Liebel contends, states will play a substantial role in determining whether abortion is legal.

“States are optimistic,” she said, “and they’re rushing to get their state in line, and saying, ‘This is where we’re coming from.’”