(I happen to be a cancer survivor myself, and knowing how the toxic drugs affected me, I can only imagine what they would do to a woman who was pregnant or the fetus she carries.)

In April of last year, Rachel Brown’s oncologist called with bad news — at age 36, she had an aggressive form of breast cancer. The very next day, she found out she was pregnant after nearly a year of trying with her fiancé to have a baby.

She had always said she would never have an abortion. But the choices she faced were wrenching. If she had the chemotherapy that she needed to prevent the spread of her cancer, she could harm her baby. If she didn’t have it, the cancer could spread and kill her. She had two children, ages 2 and 11, who could lose their mother.

For Ms. Brown and others in the unlucky sorority of women who receive a cancer diagnosis when they are pregnant, the Supreme Court decision in June, ending the constitutional right to an abortion, can seem like a slap in the face. If the life of a fetus is paramount, a pregnancy can mean a woman cannot get effective treatment for her cancer. One in a thousand women who gets pregnant each year is diagnosed with cancer, meaning thousands of women are facing a serious and possibly fatal disease while they are expecting a baby.

Before the Supreme Court decision, a pregnant woman with cancer was already “entering a world with tremendous unknowns,” said Dr. Clifford Hudis, the chief executive officer at the American Society of Clinical Oncology. Now, patients as well as the doctors and hospitals that treat them, are caught up in the added complications of abortion bans. ...