Elizabeth L. Silver is the author of "The Tincture of Time: A Memoir of (Medical) Uncertainty."
Before Obamacare, insurers could charge patients with preexisting conditions more. The new Republican health-care plan would let insurers offer plans in the health marketplaces that do it again. (Daron Taylor/The Washington Post)

My daughter had a stroke when she was 6 weeks old. More specifically, she suffered a brain bleed. More specifically, a burst arteriovenous malformation, which is sort of like a ruptured aneurysm.

Or maybe she didn’t. It might have been this injury that led to the bleed, or it might have been something else. We can’t know with certainty what caused this catastrophic event in our lives, from which she has fully recovered. But such is the nature of medicine. It is as fickle as a child. One day, it presumes it knows what diagnosis you may have; the next, it changes its mind, or realizes it was wrong or develops a new technology to determine how to fix what might have been wrong.

Of course, this wavering approach to our health isn’t a problem as long as we realize that medicine is not a perfectly understood science that always offers neat answers. If the politicians who make the laws that deal with who gets access to health care also understand this reality, we would be in decent shape. But those now holding the keys to the gates are painfully unaware of the fickle nature of the beast, and as a result, millions of patients with preexisting conditions will suffer if the proposals Congress is considering to repeal the Affordable Care Act become law.

The ACA, which banned insurers from treating patients with preexisting conditions differently from anyone else, went into effect in January 2014. My daughter was born that same month and suffered the bleed that March. Once we were discharged from the NICCU at Children’s Hospital Los Angeles after two weeks, our focus shifted from our daughter’s actual health to a realization that she’d benefited from arbitrarily fortunate timing. Apart from exceptional medical luck that would allow her to recover fully, she was also lucky that this horrible injury had happened just weeks after preexisting conditions were abolished. A mere three years later, though, the government wants to take away that luck just as quickly as it had given it.

Beyond our desire for her recovery was the gratitude that this lifelong thing, whatever it would be called, would always be covered. That the preexisting condition no longer existed. That this injury, of which she (obviously) and we had no advance knowledge and no means to prevent, would always be covered by insurance, even if we have an unforeseeable lapse in that coverage. That no matter how much we can provide for her — and we are lucky to carry private insurance — she would always have access to affordable care. She made the cut.

Parents shouldn’t be thinking of “making the cut” when in the hospital watching their children struggle to survive in the intensive care unit, or even at home in outpatient care. They shouldn’t be thinking of rising premiums or accidental windows without coverage in the future. They should be thinking of taking their children home and putting all efforts toward their recoveries. The anxiety caused by questioning whether what is happening to your child will be covered by insurance is toxic coating on an already difficult pill to swallow. We are already sick with worry about the actual health of our children; we shouldn’t also be sick over what being sick could mean to our wallets.

Because, even if infrequent, diagnoses can change, and when they do, they upend the concept of the preexisting condition in full. They may meander, shape-shift and pick up new identities and new conditions along the way, making it impossible to cut off care based on such an arbitrary label. This is at once the beauty and reality of medicine, a practice steeped in science but subject to change. Since we live in this evolving world, to have legislators draw a red line for health-care coverage is both disarming and wrong.

The House of Representatives has made its decision, passing a bill that even President Trump deemed “mean,” and the Senate is struggling, shamefully, to follow suit. Their legislation rapidly lost support, and when lawmakers return to Washington next week — after, surely, hearing from parents like us about the damage their bill would do — they will enter new negotiations, new dialogue, new contemplation, all the while positing the ongoing question of this type of coverage. Republicans claim that preexisting conditions will be covered, but most independent analysts say coverage will be diminished, watered down, inexplicably costly, lending a false promise of coverage to the reality of a return to the terrifying days before the ACA took effect. We’ve followed that path before. We — my husband and I, our daughter and millions of people like us — cannot afford to turn back to it again.

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