In general, teenage pregnancy is more common among poor girls. But poor girls who live in places with a high level of inequality — meaning that the ratio of income at the median of the income distribution to the income at the 10th percentile of the income distribution is higher than in other places — are even more likely to become pregnant as teenagers.
The new paper [by economists Melissa S. Kearney of the University of Maryland and Phillip B. Levine of Wellesley College] looks at inequality across states and finds a very similar correlation [emphasis mine] between the rate of teenage births and income inequality. For example, a teenage girl in Mississippi is four times more likely to give birth than a teenage girl in New Hampshire. The researchers conclude that teenagers in the highest-inequality states are roughly five percentage points more likely to give birth as teenagers than teenagers in the lowest-inequality states.
Inequality, the authors suggest, makes the poorest citizens believe that they have little chance of economic mobility. They are becoming pregnant “at a young age instead of investing in their own economic progress because they feel they have little chance of advancement,” the authors write.
The authors do acknowledge that a change in inequality does not explain the drop in teenage childbirth in the United States over the last two decades. That, they say, is a topic for more study.