Nebraska Gov. Jim Pillen, a Republican, signed a bill into law on Monday that bans most abortions after 12 weeks with exceptions for sexual assault, incest and medical emergencies.

The bill does not define "medical emergency" and the legislation includes a clause that will put the rules into immediate effect the day after it is signed.

LB 574, which passed the state's Republican-controlled unicameral legislature in a 33-15 vote last week, also bans gender-affirming care for people under 19 years old. The abortion amendment was tacked onto the legislation after previous efforts to restrict abortions failed to overcome a filibuster.

The bill only allows medical procedures for transitioning after a "waiting period" and "therapeutic hours" to determine if a person's gender dysphoria is "long-lasting and intense." The details of those provisions will be determined by the chief medical officer of Nebraska's Division of Public Health.

In a statement released after the bill's passage, Pillen said, "All children deserve a chance to grow and live happy, fruitful lives. This includes pre-born boys and girls, and it includes children struggling with their gender identity. These kids deserve the opportunity to grow and explore who they are and want to be, and they can do so without making irreversible decisions that should be made when they are fully grown."

The new law reflects ongoing legislative efforts around the US to restrict access to abortion and gender-affirming care. More than a dozen states have moved to restrict gender-affirming care in 2023 and more than 130 bills that target LGBTQ rights, especially health care for transgender patients, have been introduced nationwide this legislative session, according to data compiled by the American Civil Liberties Union.

Major medical associations say that gender-affirming care is clinically appropriate for children and adults with gender dysphoria, the psychological distress that may result when a person's gender identity and sex assigned at birth do not align, according to the American Psychiatric Association. But some Republicans have expressed concern over long-term outcomes of the treatments.

Some Nebraskans have expressed displeasure with the bill and many protested and filled the halls of the state Capitol last week as lawmakers spoke, resulting in the arrest of several people on Friday on charges ranging from disturbing the peace to obstructing a government operation.

ACLU of Nebraska executive director Mindy Rush Chipman said in a statement last week that the consequences of the law will be "devastating."

"To be clear, we refuse to accept this as our new normal. This vote will not be the final word. We are actively exploring our options to address the harm of this extreme legislation, and that work will have our team's full focus. This is not over, not by a long shot," Chipman said.