Aetna announced Thursday that it will not be participating in the Iowa exchanges created under Obamacare, the second insurer to leave the state this week.

Company spokesman T.J. Crawford said in an email that the decision was made "as a result of financial risk and uncertain outlook for the marketplace."

The company is still deciding whether it will sell plans in other states, Crawford said.

As the Iowa marketplace stands now, 94 counties, including Des Moines, will be left with one insurer, and the other five counties will have two, according to Cynthia Cox, associate director for the program for the study of health reform and private insurance at the Kaiser Family Foundation.

Republicans in Congress have said they are determined to pass legislation that would repeal most parts of Obamacare, but House members have been unable to agree on a bill ahead of a two-week recess that begins Thursday, and insurers have until June to set their rates for plans.

On Monday, WellMark Blue Cross Blue Shield also said it was withdrawing from the state's exchange, citing $90 million in losses as well as uncertainty about the law's future. The state uses the federal site to allow most customers to purchase health insurance that is subsidized by the government.

Aetna drew widespread attention last year when it announced that it would be pulling out of 11 states where it sold plans on the exchanges. A federal judge wrote in a recent opinion that Aetna appeared to make the move as retaliation against the Obama administration's attempt to block its proposed multibillion-dollar merger with Humana, while the company has maintained that its decision was based on massive losses, which totaled $450 billion in 2016.

Medica and Gundersen Health Plan also sell insurance in the Iowa marketplace, though one or more could leave, while another insurer could decide to enter. Shrinking options on the exchanges can result in higher premiums and fewer options, ultimately reducing access to healthcare providers that customers might prefer.