In recent months, several strict abortion laws have been passed across the United States, banning the procedure after a certain number of weeks.
Most have limited exceptions, such as in cases of incest or rape, and some only allow abortion to "save the mother's life." If the Supreme Court overturns Roe v. Wade, which it seems poised to do over the summer, this could be one of the only exceptions for abortion in many places.
For example, Arizona's 15-week ban only includes exemptions for medical emergencies when continuing with the pregnancy would "create serious risk of substantial and irreversible impairment of a major bodily function" for the mother.
And a new Oklahoma ban classifies a "medical emergency" as a condition in which an abortion "is necessary to preserve the life of a pregnant woman whose life is endangered by a physical disorder, physical illness, or physical injury, including a life-endangering physical condition caused by or arising from the pregnancy itself."
Proponents of anti-abortion bills say the language is clear and is not open to interpretation.
"The exceptions definition is very clear, specific, allows for the physician's good faith clinical judgment, and it has been upheld by the courts and is typically included in laws regulating abortion," Arizona state Sen. Nancy Barto, a Republican who sponsored the state's 15-week ban, told ABC News.
But doctors told ABC News the language of these laws is vague and makes it unclear what qualifies as a mother's life being in danger, what the risk of death is, and how imminent death must be before a provider can act.
"We've taken the Hippocratic oath to do no harm, and these types of laws and this type of language actually do harm," Dr. Melissa Simon, vice chair for research in the department of obstetrics and gynecology at Northwestern University Feinberg School of Medicine in Chicago, told ABC News. "I do not -- nor do my patients want me to -- stop what I'm doing and think about what the judge would do: 'Will the judge sentence me to jail if I were to perform an abortion?'"
"It sounds like it's straightforward criteria, but it's not in practice," said Dr. Lisa Harris.
A professor of obstetrics and gynecology at the University of Michigan, Harris told ABC News, "None of this is straightforward. It's very nuanced and complex, and it's really hard for a one-size-fits-all rule or law to generate what all patients are going to need."
Doctors ABC News spoke with said laws that only allow exceptions to save the mother's life will put the onus on the provider to prove the pregnant person is in danger of dying. In some states, providers could face charges.
Dr. Leilah Zahedi, a maternal-fetal medicine physician in Chattanooga, Tennessee, and a spokesperson for the Society for Maternal-Fetal Medicine, said the anti-abortion rights laws don't make it clear if a woman's risk of death has to be 100% for the procedure to be performed or not.
"When I see patients, for instance, who have a major cardiac problem, a lot of the time they have a risk of a major cardiac event of up to 15% to 25%, even up to 50%," she told ABC News. "At the moment they're fine. But as they get further into pregnancy, that's going to put their life more and more at risk."
She continued, "So do I have to wait until they're on death's doorstep, or can I intervene at that point to prevent more harm and more damage to them?"
There are typically three categories pregnant people fall into when they need to have abortions to save their lives, doctors told ABC News.
First are people who have serious underlying conditions -- such as heart disease, kidney failure and pulmonary hypertension, a type of high blood pressure that affects the lungs -- before getting pregnant. Continuing pregnancies would significantly threaten their health.
The second category is those who didn't have conditions before getting pregnant but now do, such as pre-eclampsia, a potentially dangerous pregnancy complication characterized by high blood pressure, or placenta accreta, which is when the placenta attaches to the uterus and potentially grows through it to other organs.
The third category includes pregnancies in which fetuses would not survive if they were born. This includes an ectopic pregnancy, which occurs when a fertilized egg implants and grows outside the uterus.
Oklahoma state Rep. Jim Olsen, a Republican who sponsored a bill that would make it a felony to perform abortions, said Oklahoma doesn't have specific definitions of what might constitute "lifesaving" to make sure an example isn't missed.
"If we tried to specify as legislators exactly what qualifies and limit it only in these situations, there's a very real possibility we could miss one ... and we don't want to inadvertently exclude something that is actually a danger to the life of the woman," he told ABC News.
He continued, "We want to fully respect the woman's right to life and all her rights, but at the same time, we must also respect the rights of the baby, and the baby has a right to life."
Medical groups have argued that what qualifies as an exception is often subjective to lawmakers, but not to the physician.
"The science of medicine is not subjective, and a strongly held personal belief should never outweigh scientific evidence, override standards of medical care, or drive policy that puts a person's health and life at risk," the American College of Obstetricians and Gynecologists said in a 2019 statement on abortion sometimes being "medically necessary."
The exceptions raise concerns about timing for abortions, doctors said.
Doctors said these exceptions make it unclear whether they have to wait to perform an abortion if a pregnancy is only dangerous once it reaches later terms.
For example, Harris said a woman diagnosed with placenta accreta is not in any imminent risk of dying before 20 weeks, but the risk is greatly heightened in the later stages.
"There is a threat to their life, but it might be months away," she said. "How imminent does that threat have to be for you to qualify for an abortion under the term 'lifesaving'?"
Another uncertainty of these laws is what occurs when a pregnant woman is diagnosed with cancer. Women who need to undergo surgery, chemotherapy and radiation may decide they want abortions so they can begin treatment immediately, Harris said.
"The threat to the life of the patient isn't imminent, meaning the pregnancy and illness are not life-threatening at the moment," she said. "But if someone, for example, were to delay treatment for eight or nine months, the cancer may advance in that instance and then they have a worse cancer when they begin to treat it."
Harris continued, "In the case of cancer, it may be that someone survived their cancer only two years as opposed to 20 years because they delayed treatment. And so that is a risk to their life if they could cut their life short."
The death of Savita Halappanavar in Ireland prompted questions about the clarity of these exceptions.
In 2012, 17 weeks pregnant with her first child, she went to University Hospital Galway complaining of back pain.
Doctors told the 31-year-old dentist that her cervix was fully dilated and that amniotic fluid was leaking. Because of this, it was unlikely her baby would survive and a miscarriage was inevitable -- but her body did not expel the fetus.
She asked if doctors could terminate the pregnancy, but they said they were forbidden to do so under Irish law because a fetal heartbeat could be detected.
"Under Irish law, if there's no evidence of risk to the life of the mother, our hands are tied so long as there's a fetal heart," an OB-GYN consultant said, according to an investigation into Halappanavar's case by the Ireland Health Service Executive, adding that "we can't predict who is going to get an infection."
Within days, Halappanavar developed sepsis, went into cardiac arrest and died.
The HSE investigation stated: "There is difficulty in interpretation of law in relation to 'what constitutes a potential major hazard or threat to mother's life.' This needs clarification."
Halappanavar's death sent shockwaves throughout Ireland, spurring the Parliament to pass an updated, clarified exception to the country's abortion ban. Six years after her death, the country voted to overturn its ban on abortion, with many voters citing Halappanavar as the reason for their vote.
Barto, of Arizona, said she does not know the specifics of the case, but believes this is a case of improper medical care rather than what can result from a denied abortion.
"I can only speculate that this woman's tragic death should and could have been avoided with proper and timely medical care and decision-making," Barto said. "Her family deserves someone to be held accountable."
Simon, of the Northwestern University Feinberg School of Medicine, said if doctors are not allowed to perform abortions because the procedure does not fall within the limits of a save the mother's life exception, maternal mortality rates in the U.S. will rise.
Data from the Centers for Disease Control and Prevention shows that between 2013 and 2018, the national case-fatality rate was 0.41 abortion-related deaths per 100,000 legal abortions. Comparatively, the mortality rate was 17.35 pregnancy-related deaths among mothers per 100,000 live births.
"Abortion is extremely safe. It is a safer procedure taking an appendix out, and that's a very common medical procedure," Simon said. "I just can't emphasize enough how safe these procedures are and how well-studied they are."
She added that maternal mortality rates in the U.S. "are embarrassing enough."
"Why do we want them to go up?" she said.