WASHINGTON — The patient had already made the agonizing decision to start chemotherapy to address her colon cancer, even though she was 30 weeks pregnant. Within a day, the decisions got harder: her colon perforated, and the pain was excruciating. She would need urgent surgery — and she would have to undergo an emergency C-section immediately.

“She looked me in the eye, and she said, ‘I have two children that need me, and if you have to make a decision, I need you to remember that. That my little girls need me, the two kids I already have need me,’” said her oncologist, Dr. Katherine Van Loon, who specializes in treating gastrointestinal cancers at the University of California, San Francisco.

Pregnant cancer patients like Van Loon’s have always faced near-impossible choices between their life-saving cancer treatments and their unborn children. But in a post-Dobbs America, restrictions on abortion access threaten to take the choice out of the patients’ hands, or those of their doctors.

Right now, one in 1,000 pregnancies is affected by a concurrent cancer diagnosis each year, a number that could rise as the mean age for pregnancy in the U.S. continues to trend upward. Many chemo, radiation, and hormone therapies can cause fetal harm, particularly during the first trimester. This can include congenital birth defects, higher stillbirth rates, and low birth weight and blood counts. Severe complications from the disease, such as those experienced by Van Loon’s colon cancer patient, may also force decisions on whether to prioritize the mother or the fetus.

The vast majority of pregnant cancer patients who choose to terminate their pregnancies do so in the first trimester, which is when the fetus is considered not viable, Van Loon said. That early, medication abortion, the most commonly used abortion method in the United States, can be used effectively. But the Supreme Court — which holds a 6-3 conservative majority — announced last week it will hear a controversial case threatening to limit access to the widely used abortion pill mifepristone, following competing lower court rulings and pressure from the Biden administration to review a Texas judge’s attempt to ban the drug. The Court’s decision in that and other abortion-related cases could also one day threaten fertility preservation efforts cancer patients rely on, experts said.

“Pregnancy is a joyful time in most women’s lives. When it is catastrophized by a cancer diagnosis, these are some of the worst moments that I have shared with patients,” Van Loon said.

Leading cancer groups have been outspoken about how continued abortion restrictions, including a potential mifepristone ban, will disrupt patient-first disease care. They say it will strip patients’ ability to prioritize life-saving treatment and interfere with physicians’ role in providing that care.

“The way that the states can regulate it would interfere with the doctor-patient relationship,” said Mary Rouvelas, Managing Counsel and Legal Advocacy Director at the American Cancer Society Cancer Action Network.

In May, the American Society of Clinical Oncology released ethical guidance for cancer physicians practicing in states where abortion access is limited.

“Oncologists have a critical role in upholding their patients’ moral agency,” the paper reads. “This includes presenting patients with options to terminate a pregnancy to treat the patient’s cancer.”

In the clinic, physicians are worried about the immediate impact a ruling would have on their ability to put their patients first. Stripping cancer patients of their reproductive choices would harm the quality of care they could provide.

“We are being limited in terms of our ability to do our best job in caring for our patients,” Van Loon said. “We know that results in worse outcomes for patients, but we also know that the moral distress that clinicians are carrying around not being able to deliver the best possible care is tremendous.”

Patient advocates, too, are worried about the impact that further restrictions on abortion access will have on patient trust.

“We need to preserve that privacy and that intimacy that happens in the doctor’s office, because a lot of these conversations are sensitive conversations or they’re scary conversations, and when there are other voices in the room, it really diminishes a patient’s ability to speak up,” Alison Silberman, CEO of patient advocacy organization Stupid Cancer, said.

Cancer groups have also noted that the post-Dobbs era poses reproductive concerns for cancer patients beyond just abortion. For those able to get pregnant, chemo and radiation can contribute to infertility, and medical experts recommend embryo preservation as one of the best fertility services for such individuals. But if states start describing personhood as beginning at fertilization, that could mean more restrictions on embryo preservation, the organizations said.

Currently, there are no laws banning egg freezing or embryo preservation, but Republicans in multiple states have introduced bills that would define personhood at fertilization. Without explicit exemptions for services such as in vitro fertilization, or IVF, there remains a legal and medical gray area. In their dissent against the Dobbs decision, Supreme Court Justices Sonia Sotomayor, Elena Kagan, and now retired Stephen Breyer explicitly named IVF as an anticipated concern.

“The Court may face questions about the application of abortion regulations to medical care most people view as quite different from abortion,” they wrote.

The Supreme Court will hear oral arguments for the mifepristone case in early 2024 and is expected to issue a ruling by the end of June.