Does Emergency Contraception Access Change Sexual Behavior Among Chilean Youth?

When Chile began making the emergency contraceptive pill available through its public health system in the early 2000s, critics warned it would unleash a wave of risky sexual behavior among the country’s youth. More than two decades later, a new study suggests the opposite occurred. Research published in Archives of Sexual Behavior finds that in Chilean municipalities where emergency contraception was available, young people were less likely to initiate sexual activity and more likely to use hormonal contraception, with no increase in the number of sexual partners. The findings challenge one of the most persistent objections to expanding access to the morning-after pill and add a surprising twist to a long-running international debate over whether easier access to contraception changes sexual behavior for better or worse.

The study, conducted by Ana Nuevo-Chiquero of the Universidad Autónoma de Madrid and the University of Edinburgh, Francisco J. Pino of the Universidad de Chile, and Pablo Villalobos Dintrans of the Universidad Mayor, exploits a quirk in how Chile rolled out its emergency contraception policy. Rather than implementing a single national mandate, the Chilean government allowed the policy to take shape municipality by municipality during the 2000s, in a country where sexual and reproductive health policies have faced intense political and religious opposition for three decades. Some local governments chose to distribute the pill through their public health centers; others declined or delayed adoption, often under pressure from conservative groups and, in some cases, legal challenges that went all the way to the country’s constitutional court.

That fragmented, essentially unstructured rollout created what economists call a natural experiment. Because adoption timing varied across municipalities for reasons largely unrelated to the sexual behavior of teenagers, the researchers could compare young people living in municipalities that had adopted the policy with those living in municipalities that had not, while statistically controlling for differences between places, across time, and among individuals. The team used multilinear regressions estimated on data from Chile’s Encuesta Nacional de Juventudes, the National Survey of Youth administered by the Instituto Nacional de la Juventud, supplementing the analysis with time, municipality, and individual-level controls to isolate the effect of pill availability from other factors that shape adolescent sexual and reproductive behavior.

The results upend the conventional risk-compensation hypothesis, the idea that people behave more recklessly when protective measures become available. In municipalities where emergency contraception was accessible, youths were significantly less likely to have initiated sexual activity at all compared with peers in municipalities without access. The researchers found no effect on the number of sexual partners reported during a year, ruling out one common form of the risk-taking argument. Meanwhile, the availability of the pill was associated with a higher likelihood of using hormonal contraception, suggesting that contact with the emergency contraceptive service did not substitute for regular contraception but rather pulled young people into the family planning system more broadly.

The authors describe two distinct channels through which emergency contraception shaped outcomes. The first is direct: by definition, the pill prevents pregnancy after unprotected intercourse, so its availability mechanically reduces the number of unplanned pregnancies among those who use it. The second is indirect and, arguably, more interesting. The very existence of the service appears to have changed behavior, delaying sexual debut and increasing the uptake of hormonal methods. This behavioral response, the researchers argue, means the pill’s public health impact cannot be understood merely by counting doses dispensed; the policy also functioned as a gateway that connected adolescents and young adults to the health system, where they could obtain information, counseling, and ongoing contraceptive care.

The finding that access delayed rather than accelerated sexual initiation is not easy to explain, and the authors are careful about the mechanisms involved. One plausible interpretation is that the presence of a confidential, youth-friendly reproductive health service changes the way young people think about sex and contraception, making planned, protected sex more salient than impulsive unprotected encounters. Another possibility is informational: visits to obtain emergency contraception, or simply awareness of its existence, may increase knowledge about pregnancy risk and the full menu of contraceptive options. Whatever the precise pathway, the direction of the effect stands in sharp contrast to the fear that animated much of the opposition to the policy in Chile, where the pill’s rollout was contested in courts and municipal councils for years before it became uniformly available.

Chile makes an unusually instructive case study. The country has one of the longest histories of public family planning in Latin America, with birth regulation programs dating back to a 1969 circular from the National Health Service, and it has experienced a full demographic transition over the past century and a half. Yet adolescent pregnancy has remained stubbornly high, and previous research by Leal and Molina documented substantial changes in contraceptive use and unplanned pregnancy among Chilean adolescents between 1997 and 2018. Against that backdrop, the fragmented municipal adoption of emergency contraception offered researchers a rare opportunity to measure causal effects in a setting where the policy landscape varied within a single country, a single health system, and a single generation of young people.

The Chilean results also speak to a mixed international literature. Studies from the United Kingdom by Girma and Paton found little evidence that over-the-counter emergency contraception reduced teenage pregnancy rates and raised concerns about behavioral responses. Work in the United States by Gross, Lafortune, and Low found that expanded access to the morning-after pill increased its use without measurably reducing fertility, while research by Atkins and Bradford associated greater availability with some risky sexual practices. Other studies, including randomized provision experiments such as Harper and colleagues’ work with young adolescents, found that giving women advance supplies of the pill increased its use but did not change sexual risk-taking. Mulligan’s analysis of US data found effects on fertility and behavior that were modest and ambiguous. The Chilean evidence, showing both a direct reduction in unplanned pregnancies and a favorable shift in sexual behavior, sits toward the more optimistic end of this spectrum and suggests that context matters: how a policy is introduced, and how it connects users to broader services, may be as important as the contraceptive technology itself.

The public health stakes are considerable. Unintended pregnancy among adolescents is associated with interrupted schooling, poorer labor market prospects, and elevated health risks for mother and child, and economists have estimated its costs in the billions of dollars annually in wealthier countries. In lower- and middle-income settings, where abortion may be restricted and adolescent motherhood more common, the calculus is starker. The United Nations has repeatedly emphasized contraceptive prevalence as a central lever of fertility decline and of progress toward gender equality, echoing a research tradition running from Bongaarts’s framework for the proximate determinants of fertility through Goldin’s work on the economic consequences of contraceptive technology for women. Against that standard, a cheap, simple intervention that both prevents pregnancies and appears to strengthen young people’s engagement with preventive care looks like a policy bargain.

The authors are cautious about generalizing beyond the Chilean context. Their estimates rely on self-reported survey data, which are sensitive to reporting bias in questions about sexual behavior, and the municipal variation in adoption, while plausibly exogenous to individual behavior, may correlate with unobserved local characteristics that the controls cannot fully absorb. The survey data also capture a period when the pill’s availability was in flux, and behavior may have responded differently once access became universal. Still, the study’s design, combining individual-level outcomes with municipality-by-time variation and a rich set of controls, represents one of the more credible efforts to measure the causal impact of emergency contraception on sexual behavior in a Latin American setting, where rigorous evidence of this kind has been scarce.

The policy implications are likely to resonate well beyond Chile. Opponents of emergency contraception in many countries continue to argue that availability encourages promiscuity or undermines abstinence-oriented messages, and such arguments have shaped access rules from pharmacy restrictions to age limits. The Chilean evidence directly contradicts the behavioral version of that argument in at least one national context, showing the opposite pattern on the key margin of sexual debut. Just as important, the finding that emergency contraceptive availability increased hormonal contraceptive use reframes the pill not as an isolated rescue technology but as an entry point into reproductive health care. For health systems searching for low-cost ways to reach young people who might otherwise remain outside their reach, the message from Chile is that the morning-after pill may do more than prevent pregnancies. It may, paradoxically, make safer sex more common.