From their abstract:
Despite a near-continuous decline over the past 20 years, the teen birth rate in the United States continues to be higher than that of other developed countries. Given that over three-quarters of teen births are unintended at conception and that over a third of unplanned births are to women using contraception, many have advocated for promoting the use of long-acting reversible contraceptives (LARCs), which are more effective at preventing pregnancy than more commonly used contraceptives. In order to speak to the degree to which increasing access to LARCs can reduce teen birth rates, this paper analyzes the first large-scale policy intervention to promote and improve access to LARCs in the United States: Colorado's Family Planning Initiative. We estimate its effects using a difference-in-differences approach, comparing the changes in teen birth rates in Colorado counties with Title X clinics (which received funding) to the changes observed in other US counties with Title X clinics. The results of this analysis indicate that the $23 million program reduced the teen birth rate by approximately 5% in the four years following its implementation, providing support for the notion that increasing access to LARCs is a mechanism through which policy can reduce teenage childbearing.I'd love to know whether the programme also had effects on STD rates. Where the price of unprotected sex goes down, you should get more of it - as Klick and Stratmann found. That's hardly a reason not to provide access, just something to consider as an offsetting cost potentially in the mix.