Health care providers have complained of an increase in patient wait times at hospitals in recent weeks, and the Trump administration has warned that the rollout of the Affordable Care Act will cause disruptions to the healthcare system.
The U.N. said Tuesday that there were about 6 million Americans who were uninsured as of last week, an increase of more than 50 million people over the past year.
It noted that the uninsured rate had dropped to a historic low of 14.5 percent, compared with 20 percent in the past.
The U.K. also reported its latest rate in its monthly survey of people under the age of 18, which fell to 15.9 percent.
The United States, meanwhile, said that it saw a 3.7 percent decrease in the number of uninsured.
The Trump administration is pushing ahead with the rollout as it tries to get Congress to approve the tax cuts for individuals and businesses, while also helping to lower the cost of the health care system.
The tax relief is expected to provide $500 billion in tax cuts over 10 years.