It’s official: Serena Williams is expecting her first child with fiance Alexis Ohanian this fall, her spokeswoman Kelly Bush Novak confirmed to The Washington Post. And indeed, as the tennis star noted, then mysteriously deleted, from her Snapchat account on Wednesday, Williams is 20 weeks along. That means she was roughly two months pregnant when she won her 23rd grand slam title at the Australian Open in January.

That realization caused a whirlwind of shock and admiration on social media, where fans couldn’t help but be impressed at Williams’s feat.

Even doctors are impressed.

“It is not easy for any woman to adapt to changes in her body, let alone while playing sport at an elite level,” Dr. Markos Klonizakis of Sheffield Hallam University told the BBC. “Physiologically, the main challenge women face within about five weeks of pregnancy is in adapting to changes to the cardiovascular system. … The nature of a Grand Slam tournament, where players have to recover to play consecutive matches, would have been a challenge for her, if you take into account nausea as well.”

Williams, of course, isn’t the only athlete, who’s competed — and even won — while pregnant.

Most famously, beach volleyball legend Kerri Walsh Jennings won a gold medal at the 2012 Olympics in London while five weeks pregnant with her third child, although she didn’t know it.

Describing herself as “moody” and “touchy” during the games to the Today Show a month later, Walsh-Jennings said it was her then-teammate, Misty May-Treanor, who suggested she might be expecting.

British Olympic cycling champion Laura Kenny also said she competed while pregnant, too.

“I actually won the with Elinor Barker when I was about five or six weeks pregnant,” she told BBC’s 5 Live radio this week. The 24-year-old is on hiatus from competition as her pregnancy progresses, but plans a full return in time for Tokyo 2020.

American Olympic swimmer Dana Vollmer also plans to snap back from her pregnancy to qualify for the 2020 games. Unlike cycling, where a larger belly might get in the way, Vollmer has continued training into her sixth month of pregnancy. She even entered a meet last week, although the five-time Olympic gold medalist was much slower than normal.

Perhaps most amazing, though, is Team USA runner Alysia Montano. At more than eight months pregnant, she competed in the 800-meter quarterfinals of the 2014 U.S. championships.

“I know there is a lot of stigma and really, the word is ignorance, behind pregnant women and exercising,” Montano told CBS LA after the race. “And the truth is, it’s good for the mom and the baby.”

Williams, who has not competed since winning the Aussie Open due to what she said has been an ongoing knee injury, has not made clear how long she plans to take off from tennis. While she remains on the entry list for the Madrid Open on May 5, it appears unlikely that she will attend.

However, as the above list of athletes has shown, it’s entirely possible to compete after pregnancy. Montano made the Olympic team ahead of the games in Rio de Janeiro last summer (although she failed to medal). Vollmer and Kenny have their eyes on 2020. Walsh Jennings made a comeback several times, including after the birth of her third child, the one she was carrying when she won her third Olympic gold. In Rio, she and new partner April Ross won a bronze.

With Williams’s baby due in September, it would be entirely possible for her to return to form by next year’s Australian Open should she wish. It’s also quite possible she’ll want an extended break. Along with her baby, Williams is also prepping for a wedding. She and Ohanian announced their engagement in December.

If she does take a longer hiatus, however, that doesn’t mean she won’t be able to execute a comeback. There’s already a precedent for that set by Kim Clijsters, who briefly retired after having a child in 2007. After nearly two years off, she returned to win the U.S. Open.