BRAINTREE -- The calls started pouring into Myrna Maloney Flynn's office after Aug. 10.

That day, Gov. Maura Healey signed legislation, titled "An Act Prioritizing Patient Access to Care," which drastically expanded late-term abortion in Massachusetts. Under the law, which will go into effect this November, abortion after 24 weeks of pregnancy will now be permitted based solely on the "professional judgment" of a physician. The previous safeguards stipulated that late-term abortion could only be performed if medically necessary to preserve the life or health of the mother or in the case of a severe fetal diagnosis. Abortions after 24 weeks will also no longer have to be performed in a hospital setting.

Flynn, the president and CEO of Massachusetts Citizens for Life, was inundated with callers concerned about the law and asking what they could do to stop it.

"There really was an organic push from outraged citizens across the state," she said.

Mass. Citizens for Life has allied with the pro-life group Massachusetts Family Action to gather enough signatures to stop the law from going into effect. They have formed the Compassionate Care Coalition to submit a petition against the law to the Secretary of the Commonwealth.

"This law is different," Flynn said. "It allows abortion up to birth on healthy, viable infants. It permits complex and dangerous induction abortions outside of hospitals, which puts women at risk."

Supporters say the act allows mothers in Massachusetts to receive care in the case of severe fetal abnormalities. Flynn, however, said she has heard from families whose doctors tell them to abort their unborn babies even if they are diagnosed with conditions that are not life-threatening.

"The bill just crosses so many fundamental lines of ethics and safety that is just completely different than any law that we've seen to date," she said.

According to the state constitution, a petition can suspend an incoming law and turn it into a ballot measure for voters to decide on in the next election. To be effective, a petition must raise the number of signatures equal to 2 percent of the votes cast in the previous Massachusetts election. In this case, the Compassionate Care Coalition must collect 49,716 signatures to suspend the law and leave it up to voters to decide in 2028 -- that is, in theory.

The state is strict about what signatures it will accept. Minor mistakes, like a smudged name or a coffee stain, can result in an entire page of signatures being thrown out. Sam Miele, director of Mass. Family Action and chair of the Compassionate Care Coalition, estimated that up to a third of signatures can be thrown out due to abnormalities. Therefore, the Compassionate Care Coalition estimates they will need 80,000 to 100,000 signatures to ensure enough are accepted.

Miele said hundreds of people across Massachusetts will be collecting signatures as soon as the State Attorney General's office creates a "fair and concise" summary for the petition to use.

"It was pleasantly surprising how much grassroots anger, how much righteous anger there was against the legislation," he said.

The petition was filed with Secretary of the Commonwealth William F. Galvin on Sept. 1. Town clerks throughout Massachusetts must receive the signatures by Oct. 23.

"It's an incredibly tight window, but it absolutely can be done," Miele said.

Volunteers across the state will be collecting signatures in the coming weeks.

"There's a whole team that's working together behind the scenes to achieve this," Miele said. "It's a lot bigger than just me or Mass. Family Action or Mass. Citizens for Life. It's gonna take everybody, and it's very doable."

Flynn said that even people who have never interacted with the pro-life movement before want to mobilize against the new law. She encouraged Catholics to "be courageous" and make their opposition to the law known on social media.

"We're really blessed to have the momentum on our side," she said. "And if the Catholic communities get involved, church by church, there's no way we can't win."