A one-month dosage of hormonal birth control pills. (Rich Pedroncelli/Associated Press)

Imagine that women regularly using contraceptives suddenly had to pay a lot more to prevent pregnancy. What would happen? The Trump administration, which rolled back mandates for companies to cover birth control last week, insists that we don’t know the answer. “The rates of, and reasons for, unintended pregnancy are notoriously difficult to measure,” the administration said in justifying the change. “In particular, association and causality can be hard to disentangle.”

Sure, separating cause from effect can be hard. But as it turns out, the country of Chile offered a perfect natural experiment on the impact of higher contraceptive prices. From December 2007 to April 2008, three pharmaceutical retailers in Chile colluded to increase the price of nearly all contraceptive drugs in the country. Prices for some birth control methods doubled.

The result was a public health disaster, as detailed in a new paper distributed by the National Bureau of Economic Research. The price hike resulted in a sharp decrease in contraceptive use in Chile, leading to a 4 percent increase in the country’s birth rate. The study also suggests that this spike in births was largely due to unplanned pregnancies, as the data shows an increase in fetal deaths, low birth weight and infant deaths. All of these are linked to neglect or lack of prenatal care — and all were on the decline before the price shock.

And the ripples go beyond health: The study’s authors report that children conceived during the period of the price shock were less likely to enroll in kindergarten, first grade and second grade.

Chile’s experience adds weight to the mountain of evidence that access to contraception does significantly reduce unplanned pregnancies. It also shows just how painful removing that access can be for mothers and their families.

Of course, we should be careful about making direct comparisons between the two countries. The United States is considerably wealthier than Chile, and abortion is illegal in Chile. So making contraceptives less affordable in the United States likely will not produce the same outcomes as in Chile.

But the point remains that restricting access to contraception has clear, long-term consequences. Babies resulting from unplanned pregnancies have much higher health risks, including lower birth weight and a lower likelihood of receiving prenatal care or breastfeeding. Mothers with unplanned pregnancies are also more likely to be younger and not married, putting their children at a disadvantage throughout life.

Other research has shown that unplanned pregnancies impose additional burdens on society in the long run, including increased crime rates and reduced labor-force participation. Plus, they put extra welfare costs on the shoulders of taxpayers to the tune of around $12 billion a year.

When the Affordable Care Act mandated that companies offer coverage for birth control as an essential health benefit, it extended access to contraceptives without deductibles or co-payments for 55 million women. The Trump administration’s decision to exempt companies with religious or moral objections threatens to take away benefits for hundreds of thousands of women.

The administration claims that it was spurred to act by legitimate concerns about accommodating employers’ religious and moral objections and that exceptions provided by the Obama administration did not go far enough. That’s a fair subject for debate.

What isn’t up for reasonable debate is whether access to contraception helps prevent unintended pregnancies. The evidence shows that it does — in the United States as well as in Chile.

Read more:

It’s time we finally offer over-the-counter birth control pills

A step forward on birth control access

We’re ceding ground in the war against infant mortality

Mammograms deserve more skepticism