As the Labor Day weekend heads into the home stretch for players and fans at the 2013 US Open, “labor” takes on a whole new meaning for three-time Open Champion Kim Clijsters. The Belgian former No. 1 is due to deliver a second child not long after the completion of the final major tournament of the year.

“This pregnancy has gone a lot faster than the first one, no real complaints,” Clijsters said in a phone interview during the US Open qualifying tournament.

This year marks the one year anniversary of Clijsters' official retirement; the Belgian had made a successful comeback in 2009 that took her to three major titles and all the way back to the top of the WTA Rankings. After playing one last exhibition in December of last year, Clijsters appears to have hung up her rackets for good.

“The first few months were pretty busy after my retirement, doing a lot of interviews…then we got pregnant almost straight away. I still work at the tennis academy that I started a couple of years ago.”

Clijsters, a WTA ambassador for USANA Health Sciences (who helped organize the interview), admits to feeling a similar sense of finality that came over her when she retired for the first time in 2007, but she has new appreciation for what it takes to balance being a mother and a touring pro.

“The first time I thought would be definite. We got married and I had Jada. Isurprised myself as much as I surprised the outside world. I tried to push it aside when that feeling first came up. This time, I know what it takes to get back into shape and travel with kids. It's different when you have a father who plays on your and the mom can just be around the kids and build a home at the tournament. I was the one trying to do all that and it just got a little too hard to keep everything in that spot.”

With the interview coming on the heels of Wimbledon champion Marion Bartoli's own retirement announcement, Clijsters spoke well of her former colleague and felt a kindred spirit with a player who understood the physical and emotional tolls that Tour life can take on a player.

“When you have such a big win like she had at Wimbledon, it's like you almost collapse, like you've achieved all you've worked for. I tried so hard for all those years to win my first Grand Slam and then when it happens you're like, 'phew, now what?'”

Though done with tennis, Clijsters clearly misses the competitive drive and physical discipline that comes with being a professional athlete.

“I'm living proof when I can say that your joints will stop hurting after a few months and you're going to want to start setting goals. Me too, I would like to try and run a marathon next year. As an athlete, we're just used to setting goals that I still have that, just not towards tennis.”

As a player who chose the site of her greatest triumphs to end her career, the 30-year-old Clijsters feels a tremendous sense of peace with her career and her decision to end it for good.

“[The US Open] is such a great event that I actually really look forward to watching it on TV. If I wasn't pregnant, I would have been there. I would have enjoyed seeing the players and being on site and watching the big matches.”

Despite being off the court, the four-time major champion has maintained a strong presence in the tennis world, commenting on matches via her Twitter (@clijsterskim) and serving as a part-time coach/constant to compatriot Kirsten Flipkens. But Clijsters is happy to remain firmly on the sidelines, the desire to compete at the highest level no longer there.

“I don't miss it. It's not like I'm sitting in front of the TV when the US Open comes on and saying, 'Oh, I wish I was there.' No, not at all.”

On Flipkens' run of good form that culminated in a run to the Wimbledon semifinals, Clijsters was complimentary and was happy for her longtime friend.

“The last year and a half has been an incredible ride. [Flipkens] had some problems, some blood clots and with her federation, so she came up to my door and we've been friends since she was 6 and I was 8. For me, this is a step up to more like being a mentor. Before we were friends, we would go to parties or we would train together. This is more serious, for me to try and help her out with my experience for the next step in her career.”

A tennis player is used to having a singular focus and a tunnel vision approach to success, but Clijsters has clearly enjoyed the shift into mentor and motherhood, even pausing our conversation to tend to five-year-old Jada.

“She's watching TV and she's crying because a dog lost its owner. She's an animal lover.”

That's the life these days for the former No. 1, and Kim Clijsters would not have it any other way.