Last year, the star athlete won her seventh Australian Open - while eight weeks pregnant, thank you very much. She later gave birth to daughter Olympia in September, and then Wednesday Alexis Ohanian and in November.
But her form isn't ready for Grand Slam action, she said.
Just one win in last eight starts
The Philadelphia Flyers are averaging 2.8 goals per game and are scoring on 20.4 percent of their power play opportunities. Jakub Voracek (eight goals, 40 assists) and Claude Giroux (13 goals, 35 assists) will lead the attack for the home team.
After 11 months off, Williams was defeated 10-5 in a supertiebreaker after she split the first two sets with French Open champion Jelena Ostapenko in an exhibition match at the Mubadala World Tennis Championship. Despite this, she made it clear afterwards that she missed being on court and was desperate to play at Melbourne Park, where she has been crowned champion seven times.
The professional athlete was scheduled to defend her title later this month.
Virgil van Dijk makes Liverpool debut
The Brazil global charged back at the defender and angry words were exchanged between the two. However, he repaid them in fine style to spark wild celebrations at his new home.
Australian Open tournament director Craig Tiley said Williams waited as long as she could before letting organizers know she wouldn't be able to compete.
Williams, whose Grand Slam tally is just one shy of the all-time record held by Australian Margaret Court, said she was disappointed to withdraw, but looked forward to returning in the future.
Few players have successfully bounced back after giving birth, and even fewer have managed to go on to win Grand Slam titles. Commencing from January 15, many big names will be missing from the Australian Open this year due to health issues. Murray has returned home after failing to recover from a hip injury sustained a year ago, while Nishikori has been on the sidelines since August due to a torn tendon in his right wrist.
Ribéry revient sur sa relation tumultueuse avec Gourcuff
On disait 'Ribéry a giflé Gourcuff', 'regardez comment il l'a regardé de travers', 'Gourcuff il a peur de Ribéry'... Il s'est servi de ça parce qu'on était dans une situation très difficile, et où il fallait des coupables.
There is also uncertainty over whether former champions Novak Djokovic, Stan Wawrinka and Rafa Nadal, the latter of which arrived in Melbourne earlier on Friday, will be fit to take to the court.