Nicole Miller had gone to the emergency room in Boise, Idaho, after waking up with heavy bleeding in her 20th week of pregnancy. By afternoon, she was still leaking amniotic fluid and hemorrhaging and, now in a panic, struggling to understand why the doctor was telling her that she needed to leave the state to be treated.

“If I need saving, you’re not going to help me?” she recalls asking. She remembers his answer vividly: “He told me he wasn’t willing to risk his 20-year career.”

Instead, that evening, hospital workers at St. Luke’s Boise Medical Center put Ms. Miller on a small plane to Utah, where she said she gripped her husband’s hand — scared of flying but more terrified that she would never see her young daughters again. “I just need to stay alive so I can be around for my two other kids,” nurses reported her saying as she arrived at the hospital in Salt Lake City, 14 hours after she had arrived in the emergency room back home.

Only when she woke up the next morning did she understand, because a nurse told her, that she was airlifted so she could have an abortion.

“I couldn’t comprehend: I’m standing in front of doctors who know exactly what to do and how to help and they’re refusing to do it,” Ms. Miller said in an interview, her first since going through the ordeal last fall.

On Thursday, the United States Supreme Court declined to decide whether states that ban abortions, like Idaho, must comply with a federal law that requires emergency room doctors to provide abortions necessary to protect the health of a pregnant woman.

The justices sent the question back to the lower courts for trial, and in the meantime reinstated a lower-court order saying that the federal law, the Emergency Medical Treatment and Labor Act, did apply.

Abortion opponents accuse the Biden administration of trying to use the federal law to turn emergency rooms into “abortion havens.” Exceptions to abortion bans, they say, already give doctors the same leeway to provide abortions in true medical emergencies.

The Biden administration’s push to apply the law “is a P.R. stunt to spread the lie that pro-life laws prevent women from receiving emergency care,” Katie Daniel, the state policy director for Susan B. Anthony Pro-Life America, said after the court ruling on Thursday.

But doctors in Idaho and other states with near-total bans say that even with the renewed protection of federal law, they have little clarity about what medical emergencies are covered, and little reassurance that they will not face charges, jail time, large fines and loss of their medical licenses if they provide care a prosecutor says was not necessary.

“The transfers and the difficulty finding OB-GYNs who are willing to do the care are going to continue,” said Dr. Alison Haddock, the president-elect of the American College of Emergency Physicians, who is leaving her job in Houston this week for a position in the Pacific Northwest, in part because of the difficulty of working under Texas’ abortion ban.

Ms. Miller’s case illustrates the struggle for doctors. When she arrived at the emergency room at St. Luke’s in Boise just before 6 a.m. on Sept. 11, the federal law was under effect, because of the lower court ruling.

According to her account, which was verified by The New York Times, she had placental abruption and her water had broken prematurely, but doctors at St. Luke’s said they could not legally give her the care she needed. By the time they put her on the plane to Utah, they estimated she had lost a liter of blood.

Doctors at St. Luke’s, Idaho’s largest hospital system and biggest employer, say there was even more uncertainty after the Supreme Court temporarily suspended the law in January. In the four months after that, the hospital airlifted six pregnant women to other states for care; the previous year, there was just one, presumably Ms. Miller. (The hospital declined to discuss her case specifically, citing privacy laws.)

Raúl Labrador, Idaho’s attorney general, a Republican, has questioned those numbers, noting that the doctors were not under oath when they provided them. “I would hate to think that St. Luke’s or any other hospital is trying to do something like this just to make a political statement,” he said after the Supreme Court heard oral arguments in the case in April.

Ms. Miller, now 39, will tell her story under oath this fall, as a fact witness in a lawsuit brought against the state by the Center for Reproductive Rights. “I want people to know that this can happen to anyone, it can happen to your sister, your wife or your daughter,” she said. “I never expected this to happen to me.”

She and her husband, Michael, had debated whether to have a third child. It took longer than expected, but they were thrilled when she became pregnant through intrauterine insemination, and even more excited when they found out they were having a boy.

They had already named him — Maddox David — when Ms. Miller started spotting around 17 weeks of pregnancy. Her obstetrician could see from ultrasounds that she was leaking amniotic fluid, and suggested a maternal fetal medicine specialist.

Before Ms. Miller could see the specialist, she woke up hemorrhaging. She called her mother to watch her girls, then she and Mr. Miller went to the emergency room.

Ms. Miller said that doctors told her that the fetus still had a heartbeat, and that she would need to leave Idaho for care. They transferred her first to a labor and delivery triage unit, where doctors said the fetus was in danger. As the doctor told Ms. Miller that he could not risk his career to give her the care she needed, the medical student standing next to him cried. “I’m assuming that was because she was in shock as well as to what was happening,” Ms. Miller said.

Still, no one mentioned abortion, or termination, she said. “It was, ‘We need to get you to a place where you have all of your options.’”

Ms. Miller knew little at the time about the Idaho law that bans abortion except to prevent the death of a pregnant woman, for some nonviable pregnancies, or in some cases of rape and incest.

Looking back, she can see that the law placed the doctor in a difficult position. “They have a lot of risk as well,” she said. “But it doesn’t take away from how it traumatized me to be in a hospital where you are supposed to be taken care of — and to be told, ‘We can’t do anything for you.’”

She was taken by ambulance to the plane with her husband, a nurse and a paramedic. The nurse “just kept looking at me and shaking his head that I was going to be OK and that he had me, because he could physically see how terrified I was.” Ms. Miller said. “He really was the first person that day that showed any kind of compassion.”

Ms. Miller’s mother and daughters raced by car to meet them in Salt Lake City, a five-hour drive.

In Salt Lake City, the procedure, a dilation and evacuation, went smoothly. Ms. Miller was discharged two days later; she and her husband returned days after that to pick up the remains of the fetus.

Doctors and hospitals in Idaho say they, too, have been on what the chief executive of the state’s medical association, Susie Pouliot Keller, called a “roller coaster” since Roe v. Wade was overturned two years ago, triggering Idaho’s abortion ban.

The state has lost nearly a quarter of its OB-GYNs and more than half its maternal-fetal medicine specialists since abortion bans took effect two years ago, many citing the uncertainty and difficulty of providing necessary care under the ban.

The Supreme Court’s decision on Thursday offered some relief, said Dr. Duncan Harmon, an OB-GYN at St. Luke’s. Still, he said, there are cases where the law does not make clear if an abortion is allowed.

He has to consider the threat of criminal penalties and jail time, for himself and his family. “I want to work in the best way I can to care for my patients, but my top priority is to my family,” he said. “I would love to be a martyr for my job, but not all of us can do so.”

Ms. Miller has seen a maternal fetal medicine specialist to discuss trying again for a third child. The doctor told her that the risk of placental abruption, while low, was slightly higher for women who had experienced it before.

“It’s something that I struggle with every day,” Ms. Miller said. “Because as much as I want to try again to have another baby, I also have two little girls that need me.”

She added: “If I were to end up in that situation again, it could go in any direction. The fact that I don’t have someone here that I could fully trust to help me, it seems like an impossible decision.”