Clinics that call themselves crisis pregnancy centers are not obliged to tell women when state aid may be available to obtain an abortion, according to a US supreme court ruling that represents a blow to pro-choice groups.

Crisis pregnancy centers are storefronts which have the look and feel of women’s health clinics, but are often backed by Christian groups that try to persuade women not to have abortions. The split ruling by the justices, coming from a case in California that went all the way to the supreme court, is a win for anti-abortion groups, which have gained ground under Donald Trump’s administration.

“We are pleased that today’s decision protects Americans’ freedom of speech,” said Jeff Sessions, the attorney general, after the ruling. “Speakers should not be forced by their government to promote a message with which they disagree, and pro-life pregnancy centers in California should not be forced to advertise abortion and undermine the very reason they exist.”

He continued: “This department will continue to vigorously defend the freedom of all Americans to speak peacefully in accord with their deeply held beliefs and conscience.” Anti-abortion groups called the decision on Tuesday a “win for life”.

America’s highest court legalized abortion in the landmark 1973 decision in Roe v Wade. Since, abortion foes have sought to chip away at those rights and have accelerated their efforts under Trump, who has been supportive of their cause.

The new decision is a significant victory for groups that operate pregnancy centers. As the ruling was announced, reproductive rights protesters were already outside the court. The justices sent the case back to lower courts, where the law requiring clinics to tell low-income women about abortion options is likely to be struck down.

“We will not stop fighting. This is not about abortion – this is about controlling women,” said Ilyse Hogue, the president of pro-choice group Naral, told protesters.

In an opinion written by the conservative Judge Clarence Thomas and joined by the court’s swing vote, Justice Anthony Kennedy, the opinion ruled California’s law would be “unduly burdensome”, that it would “chill” the protected speech of employees of anti-abortion clinics, and the state “has offered no justification that the notice plausibly furthers”. All three of the court’s female members dissented, in an opinion joined by Justice Stephen Breyer.

There are roughly 2,700 crisis pregnancy centers in the United States, including about 200 in California. The clinics vastly outnumber health clinics where women can obtain abortions.

California officials said some centers mislead women by presenting themselves as reproductive health facilities, going so far as to resemble medical clinics, down to lab coats worn by staff.

California’s Reproductive Fact Act required licensed family planning facilities to post or distribute notices about state programs offering free or low-cost birth control, prenatal care and abortion services. The law also mandated unlicensed centers, which may have no medical provider on staff, to inform women about these programs.

Crisis pregnancy centers don’t have to tell women the truth because of the first amendment. Ok fair enough. So how exactly does anyone justify the many anti-abortion laws that require doctors to read patients a script telling abject falsities about the risks of abortion? — Jill Filipovic (@JillFilipovic) June 26, 2018

Reproductive rights advocates compared the law to the kind of information anti-abortion campaigners compelled doctors to read to patients in some states, even though, in some cases, the material contained errors of scientific fact.

In one case cited by Justice Elena Kagan’s dissent, Akron, Ohio once passed a law requiring doctors to tell women about the “physical and emotional complications” that may occur after an abortion, and “the unborn child is a human life from the moment of conception”. That statute was found to be unconstitutional by the court.