FRIDAY, Feb. 27, 2026 (HealthDay News) — For most teens, turning 19 is a milestone of early adulthood. But for those relying on Medicaid, it often triggers a birthday cliff where health insurance simply vanishes.

A new study from the University of Chicago highlights a systemic issue: The moment a person is no longer classified as a child by the government, their risk of becoming uninsured soars.

It looked at more than 9.4 million Medicaid enrollees across 47 state Medicaid programs born between 1991 to 2001.

The study, published recently in JAMA Pediatrics, found that 35.6% of these young adults without chronic health issues were disenrolled from Medicaid at age 19. 

Medically complex patients — those with conditions like cystic fibrosis or heart disease — were also affected. While they were more likely to keep coverage than their healthier peers, 13% still lost their insurance the moment they turned 19.

The researchers found that where a young adult lives is often the biggest factor in whether they stay insured. In some states, the risk of a medically complex person losing coverage by age 21 was as low as 3%. In others, it was as high as 37%. For healthier young adults, the gap was even wider, with disenrollment rates hitting nearly 84% in certain regions.

“I was really surprised at the variation among states,” lead author Betsy Cliff, an assistant professor at UChicago, said in a news release. “Two equally sick people living in different places can have a very different probability of losing health insurance.”

Some factors boosted the chance of becoming disenrolled from Medicaid insurance at age 19: Being male; having income-based versus disability-based coverage; living in a state that has not expanded Medicaid to all low-income individuals; and living in a state where managed care health plans dominate.

The study noted that patients with complex conditions, particularly mental health and heart conditions, were among the most likely to lose their coverage. 

Without insurance, researchers said these individuals often skip maintenance medications or miss appointments with specialists, which can lead to expensive and poorer outlooks for these folks.

The researchers pointed out that the system often fails because it is too complex to navigate without help. Many 19-year-olds are also aging out of school systems or pediatric offices that previously helped them with paperwork.

“Individuals face so many changes when they turn 19. … It’s a very stark example of how arbitrary the health insurance system can be,” Cliff noted.

Only about a third of people who lost insurance successfully got it back, the study showed. Of the young adults who lost coverage, 38% of those with complex conditions and 29% of those without complex conditions reenrolled within 12 months of losing coverage.

Cliff suggested that offering care navigators could help prevent these insurance gaps.

“This description provides an example of the patchwork and somewhat arbitrary nature of health insurance that is a key feature of the U.S. health system," the researchers concluded. "This work adds to evidence that the myriad policies that govern Medicaid coverage result in differential risks of disenrollment by condition and geography, which can lead to disparities in health care access and health.” 

More information

Learn more about how to maintain coverage through the Medicaid and CHIP official transition guide.

SOURCES: University of Chicago Medical Center, news release, Feb. 24, 2026; JAMA Pediatrics, Feb. 16, 2026