Former world No 1 Martina Hingis expressed doubts on Monday on any surprise participation at the 2012 London Olympics, the five-time Grand Slam winner content with her life after tennis.

The 30-year-old played a pro-am on opening day at the San Diego Open, then all but ruled out a return, even if the invitation to play mixed doubles at the Games came from the camp of countryman Roger Federer.

"I'm not really thinking about it at all," Hingis said. "The invitation has been blown a bit out of proportion. I may be retired but the competitive instinct is still there.

"My life is pretty comfortable now and I'm really enjoying it."

The former teen star dominated from 1997-1999, but quit the game in 2007 without contesting a positive test for cocaine after proclaiming her innocence.

Were she to somehow reconsider the offer, Hingis would then have to - under strict ITF regulations - make a return to the WTA (if only in doubles), make herself available for the Swiss Fed Cup team and also become available for doping tests.

That means relentless anti-doping monitoring that requires current players to report their intended whereabouts to international authorities down to the hour on a daily basis.

Such a requirement could well be the deal-breaker for Hingis, who has spent a month in North America between playing TeamTennis, organising a new sponsorship and making promotional appearances.

In addition, Hingis played Wimbledon women's veteran doubles at Wimbledon with Lindsay Davenport, her former rival who just announced she is pregnant again.

"Definitely I would have to play some tournaments, like mingle around, play some doubles, some mixed at Grand Slams," Hingis said. "But that's another issue if you want to go through all that."

Hingis is married to Frenchman Thibault Hutin, who like herself is immersed in the equine world of show jumping.