Sarah Green Carmichael

Ohio voters on Tuesday passed a measure enshrining the right to abortion in the state’s constitution. The outcome, the latest in a string of ballot-measure victories for reproductive freedom in conservative-leaning states, was an affirmation of women’s right to make decisions about their own bodies. The people who read political tea leaves for a living are  saying the abortion issue may help Democrats overcome voters’ persistently bad feelings about the economy.

Although abortion is often talked about as the archetypal culture war battle — in contrast to so-called “kitchen table” concerns like inflation — whether and when to have children is one of the biggest economic decisions a woman can make. New research highlights just how important reproductive autonomy is to women’s earning power. Unintended pregnancies have a lasting and harmful effect on women’s careers, a study led by economists at the University of Chicago found.

The scholars used Swedish administrative data to look at what happened to women who got pregnant while using long-acting, reversible contraception, such as an IUD or an implant.

Although this happens in only about 1% of users, that’s still a lot of pregnancies. In 2017, about 10% of women in the US who were using contraception had an IUD or implant. At a 1% failure rate, that would be almost 50,000 unplanned pregnancies a year.

In the study of Swedish women, about three-quarters of women whose contraception failed went on to give birth. The impact was clear. “We find that unplanned pregnancies have substantial, negative, and lasting consequences on the careers of previously childless women,” the authors write. Seven years later, these women have a 20% lower chance of being in a skilled occupation. Women ages 22 to 27 were earning about a third less than they otherwise would have been earning; women over 28 were earning about 13% to 16% less.

Using the administrative data allowed the researchers to track women of similar backgrounds for several years before and after the random failure of their birth control method. “We can see these women on similar paths, and then the paths just diverge when one group of them gets pregnant,” says Juanna Schrøter Joensen, an economist at the University of Chicago and a co-author of the study.

Planned pregnancies, by contrast, had much smaller economic downsides. Women who were able to delay pregnancy until a time of their choosing experienced only half the earnings penalty of those who became pregnant by accident. It did not reduce their likelihood of advancing to a skilled occupation.

Unplanned pregnancies are especially costly because they’re more likely to happen when women are younger. They make it harder to switch to higher-earning industries and stop women from moving into management positions and other higher-paying roles. Pregnancies that interrupt education are especially expensive, costing women 37% to 39% of future earnings.

Although abortion is readily available in Sweden and covered by the national health plan until 18 weeks of pregnancy, only about one in four women in the study chose to terminate. Those who did tended to earn a bit less and be in lower-skilled jobs. (There was no meaningful difference by age.) After the abortion, their careers continued largely as if the pregnancy hadn’t happened.

But that wasn’t the case for the women who went on to give birth. Essentially, an unplanned birth freezes a woman’s economic potential. She never finishes that graduate degree. She doesn’t move to that bigger job. She doesn’t have the same chances to discover what she’s really good at.

On the flip side, women who get pregnant on purpose generally wait until their careers are more established. While motherhood can hurt their earnings — even in egalitarian Sweden — the impact is much smaller. And when women delay pregnancy until they’re older, the career downsides are minimal.

There are some limitations to the research. Most notably for our purposes here, the data is drawn from Sweden, where parents share 16 months of paid leave, universal health care and subsidized child care. It’s possible that motherhood penalties would be even higher in countries without these supports, such as the US.

Nonetheless, the study highlights that economic opportunity rests on a foundation of bodily autonomy. If you can’t control when you give birth you will have a much harder time exerting control over the rest of your life.

More than 20 years ago, Nobel Prize-winning economist Claudia Goldin showed that the introduction of the birth control pill had a transformative effect on women’s careers. But today, as the abortion debate plays out in state after state across the US, it’s worth remembering that no method of contraception is perfect. Elective abortion will always be a vital option. Voters in Ohio — and before them,  Kentucky, Kansas, Michigan and Montana — have shown they know that.

Sarah Green Carmichael is a Bloomberg Opinion columnist and editor. Previously, she was an executive editor at Harvard Business Review.