Association of reproductive access restrictions and out-of-state abortion care in Colorado: an interrupted time series analysis for 2018 to 2024.

Objective: Access to abortion has changed dramatically in the United States in recent years, both at the federal and state level. For nearly 50 years, the right to abortion was considered a federally protected right under the Roev. Wade (1973) recognition of privacy rights under the 14th Amendment. In September 2021, Texas passed State Bill 8 which implemented a 6-week restriction on access to abortion. The following year, in 2022, the Supreme Court issued the Dobbs v. Jackson Women's Health Organization decision. Dobbs reversed Roe v. Wade and shifted determinations about legal access to the states, several of which already had trigger bans awaiting the potential removal of this constitutional right. To explore how these legal alterations to access are associated with changes in travel into abortion rights-protective states for abortions by residents of abortion-restrictive states, we sought to measure monthly abortion trends. Specifically, our goal is to compare monthly abortion utilization in Colorado by resident status before and after the introduction of abortion access restrictions, while adjusting for overall temporal trends.

Study Design: Utilizing monthly count data for induced abortions from the Colorado Department of Health and Environment from 2018 to 2024, an interrupted time series analysis was used to assess the association between changes in federal and state law and the number of out-of-state patients traveling to Colorado for abortions. Secondary analysis focused specifically on Texas residents. Quasi-Poisson time series regression models adjusted for time in two ways: first, we used a linear time adjustment to account for any long-term trends and second, we used harmonic terms to account for any seasonal variation present in the data.

Results: Out-of-state residents were over twice as likely to travel to Colorado after Dobbs compared to before: rate ratio (RR), 2.14 (95% confidence interval, 1.54, 2.99; P<.001). Texas residents were over 7 times more likely to travel to Colorado for abortions after the enactment of State Bill 8. Rate ratio, 7.86 (95% confidence interval, 3.30, 20.09, P<.001). Although initial spikes in travel to Colorado, particularly by Texas residents, have shown a gradual reduction over time, these patterns have not returned to baseline. This may indicate a long-term shift in how abortion care is provided and obtained in the United States in the wake of changes in the law.

Conclusion: There has been a substantial increase in the number of patients traveling to Colorado for abortions associated with changes to both federal and state laws, carrying implications for clinicians and patients alike. While some of the initial demand for abortions from out-of-state residents appears to have reduced in Colorado, it has not returned to baseline and may reflect a permanent shift in how and where abortion care is provided.