An antiabortion group that mounted a six-month undercover investigation has released videos this week that raise questions about what might happen to a baby as a result of an unsuccessful abortion.

One video features a D.C. doctor, Cesare Santangelo, who said that in the unlikely event that an abortion resulted in a live birth, “we would not help it.” Santangelo was answering repeated questions from an undercover operative about what would happen, hypothetically, if she gave birth after an unsuccessful abortion.

“I mean, technically, you know, legally, we would be obligated to help it, you know, to survive, but . . . it probably wouldn’t,” Santangelo is shown telling the woman, who was 24 weeks pregnant. “It’s all in how vigorously you do things to help a fetus survive at this point.”

Live Action president Lila Rose said the group’s videos expose “truly gruesome, illegal and inhuman practices.” She defended the tactics, saying undercover investigations are a powerful method to expose abuses.

In an interview with The Washington Post, Santangelo said he was trying to reassure the woman, who turned out to be an undercover operative of the group, Live Action. In reality, he said, he would call 9-1-1. But he said he stands by what he said on tape.

“What I said is, basically I wouldn’t do anything extraordinary,” he said Saturday. “We would call EMS. We would call 9-1-1. But I wouldn’t do intubation or anything. . . . You let nature take its course.”

The videos do not depict Santangelo doing anything illegal. Live Action provided an advance copy of the video, and other extended footage of the D.C. clinic encounter, to The Post on the condition that it not be published before Monday. Also on the extended tape is a nurse saying unequivocally that the clinic would take any live birth to a hospital. Under D.C. law, it is generally permissible for one party to a conversation to record it without consent.

Live Action plans to release more videos as part of a campaign targeting clinics that perform abortions late in pregnancy, also known as “late-term” abortions. It claims that the videos show that abortion doctors are willing to kill babies in violation of the federal Born-Alive Infants Protection Act of 2002, which requires them to try to save a child born during a failed abortion using the same measures used in miscarriages or preterm births at the same stage of pregnancy.

No authorities have accused Santangelo of violating the law. His attorney, Alfred F. Belcuore, said the doctor practices medicine in full compliance with laws in the District of Columbia. In a statement, he criticized the recording of “a private exchange between a physician and his patient” and their release as an “outrageous intrusion upon the doctor-patient relationship.”

Another video released Sunday shows an unidentified worker in the Bronx saying the clinic would put the baby in a jar of “solution” that would cause it to stop breathing. Marjana Banzil, director of the Bronx clinic, said Friday she had not viewed the video but that any employee who would say such a thing was misinformed.

“I have never had any fetus that was born alive,” she said. “If my staff member or somebody had mentioned something [like that], it was something they didn’t understand.” Live Action is calling for investigations of the Washington Surgi-Clinic and Dr. Emily Women’s Health Center in the Bronx.

Experts say it is exceedingly rare for a live birth to result from an abortion attempt. Santangelo and other doctors said they have never witnessed it. But interest in the subject has been rekindled during the trial of Philadelphia doctor Kermit Gosnell, who is accused of snipping the spines of living babies after they were removed from their mothers’ bodies.

The group outfitted three women between 23 and 26 weeks pregnant with tiny cameras and sent them to 18 clinics pretending to seek abortions. They were unable to gain access to other clinics because of scheduling conflicts and because they were too far along in their pregnancies. Rose said the women were recruited and paid between $1,000 and $2,500.

The videos come at a time of particular upheaval over abortion. Several states have passed laws severely restricting access to the procedure, which abortion rights groups have challenged or intend to in court. Many of those laws target early-stage pregnancy, but in recent years, late-term abortions have been more controversial. Most states have some restrictions on late abortions, according to the Guttmacher Institute, a nonprofit reproductive health research center.

In Maryland and Virginia, abortions are not allowed beyond when the fetus becomes viable, except in situations where the woman’s “life and health” are threatened. Maryland also allows exceptions for fetal abnormalities. In both states, the doctor performing the abortion makes those determinations. In Virginia, a second doctor must approve it.

The District has the fewest restrictions, with no specific rules governing late-term abortions.

More than 88 percent of the 1.2 million abortions performed each year in the United States are done in the first trimester, and most doctors will not perform them beyond 24 weeks because of moral qualms, legal concerns or lack of experience. Barely 1 percent of procedures — perhaps about 15,000 each year — are done after 21 weeks. At 37 weeks, a baby is generally considered full-term. No group has statistics on how many fetuses survive an abortion, experts said.

But it can happen when doctors use suppositories to help open a woman’s cervix days before the abortion. The suppositories can, in rare instances, trigger labor.

Bonnie Hope Arzuaga, a Chicago neonatologist who co-wrote a 2011 study in the journal Pediatrics that looked at the limits of viability, said the lack of clarity in the federal Born-Alive law often leaves the decision up to the states and the individual doctor.

“You have to use your professional judgment, you have to use ethical principles, and a lot of times law and ethics don’t agree,” she said. People don’t realize that physical intervention to resuscitate a 23-week-old infant can cause major damage to its lungs and brain, she said.

When patients with wanted pregnancies deliver prematurely at 23 to 26 weeks, she gives the woman or parents a choice, laying out what may be in the best interest of the baby and its quality of life. “Do they want us to ‘do everything,’ or do they want us to provide comfort care, wrap the baby in a blanket and let them hold it until it passes away?”

Live Action was founded by Rose, a former associate of conservative activist James O’Keefe, whose controversial stings contributed to the demise of the liberal group ACORN. She has used similar techniques in her campaign against Planned Parenthood, employing actors to infiltrate clinics to provoke clinic workers into condoning child sex trafficking or sex-selective abortions.

Santangelo, 56, said he’s been a practicing obstetrician-gynecologist in the District since 1987. He said he keeps a low profile, partly because he worries that the controversial nature of abortions could make him a target for violence, but also because he prefers to stay out of the politics. He said he sometimes refuses late-term abortions if he feels women have been coerced or are in extramarital affairs, are seeking to terminate because of the sex of the child, or seem unsure whether they want the procedure.

He said he views what he does as a service because some are victims of rape and incest. The majority are women with wanted but abnormal pregnancies.

When a patient is seeking a late-term abortion, he said, he will insert a suppository to open her cervix. Two days later, he said, he completes the procedure by cutting the umbilical cord until the cord stops pulsing. Then he removes the fetus. He said he has never had a live birth during an abortion.

He said he was “tripped up” by a hypothetical at a moment when he was trying to reassure a client. “Once the baby is born, it’s out of everybody’s hands, and the baby has rights, too,” he said. “I understand that and I support that.”

He said he has not watched the video because “I don’t like to feed into these people. I really consider them terrorists.”

Alice Crites contributed to this report.