The recession and high travel costs might explain why one major medical tourism survey found fewer patients going abroad for care now than two years ago.

But those factors alone don't explain why those within the industry are ratcheting down their expectations and acknowledging that the number of medical tourists will never come close to the 20 million a year by 2015 predicted a year ago.

Going overseas for medical procedures is pitched by advocates as a less-expensive alternative to care in the United States. But industry growth is being held back by numerous factors.

Medical tourism's mainstay is elective procedures. But the recession has left more people without insurance and postponing elective procedures in general, whether done in the U.S. or elsewhere.

Gas prices of 2008, and a subsequent rise in travel costs, made it more expensive to travel for care. Even with a fall in oil prices, compared with last year, airfares are still more expensive than they were pre-2007, as airlines cut capacity to protect profits.