Two insurers announced this week that they would pull out of Iowa's Affordable Care Act exchanges next year, raising worries that the decisions could be the leading edge of a trend. Insurers face approaching deadlines and major uncertainties about the short-term viability of the exchanges, and beyond, because of politicians' inability thus far to move a specific repeal and replace plan forward.

Aetna spokesman T.J. Crawford said that the company had informed federal and state regulators that it would not offer plans in Iowa's exchange because of "financial risk and an uncertain outlook for the marketplace" on Thursday. That followed the announcement Monday that Wellmark Blue Cross and Blue Shield would also pull out of Iowa's marketplaces next year.

The combination of the two exits will leave the vast majority of counties in the states with only one insurer, assuming that there are no other changes, according to Cynthia Cox of the Kaiser Family Foundation.

“While we have seen signs that the market is moving toward stabilization, generally speaking, there are parts of the country that are likely fragile and at high risk of losing insurers or having premium increases,” Cox said. “There’s a lot of uncertainty around repeal and replace; it’s not clear what the Trump administration may do around the individual mandate or cost sharing subsidies and without more clarity from the administration and Congress, insurers are likely very hesitant to participate in the individual market.”

She said the departures weren't entirely unexpected. Wellmark had been slow to enter the exchanges. Aetna pulled out of most of the markets where it sold exchange plans last year, and its chief executive has described the marketplace as in a “death spiral.” Crawford said that Aetna had not made decisions yet about whether it would continue to sell insurance in Delaware, Nebraska and Virginia for 2018.

“We are very concerned about this development, but Iowa is not alone as Affordable Care Act markets around the country are being left with few to no options available to consumers,” Iowa Insurance Commissioner Doug Ommen said in a statement after the Wellmark departure was announced. His spokesman did not immediately respond to a request for comment.

The Wellmark departure will force 21,400 Iowans to search for a new plan. Aetna did not disclose its state-specific exchange membership, but currently insures roughly 240,000 people on the exchanges in four states.

Wellmark's departure was quickly seized on by the Trump administration as evidence that the exchanges were failing and that the Affordable Care Act needed to be repealed.

“This development is further evidence that Obamacare is fatally flawed and unsustainable. As the law continues to fail on its own, more Americans are presented with higher healthcare costs and fewer options for coverage,” Alleigh Marré, a spokeswoman for the Department of Health and Human Services, said in a statement. “Repealing and replacing the law remains the best option and administrative action alone cannot save it.”

Deadlines vary by state, but insurers must decide in May and June whether they will file to participate in the marketplaces for 2018, even as they remain uncertain about whether there will be funding for cost-sharing reductions that help lower income people afford their deductibles and co-pays.

Large insurance companies are bowing out of health care exchanges citing financial losses. Here’s what that means for Obamacare. (Daron Taylor/The Washington Post)