According to reports, the 35-year-old tennis pro checked in St. Mary's Medical Center in Palm Beach, Florida, on Wednesday, with an entire floor of the hospital being cleared in order to ensure the mother-to-be has the maximum amount of privacy possible.
Serena, who announced her surprise pregnancy with Reddit co-founder Alexis Ohanian, 33, back in April, is reportedly due to give birth on Friday, after doctors made the decision to induce her on Thursday night.
Local news outlet CBS12 reported on Friday morning that doctors have confirmed that Serena was admitted to the hospital on Wednesday, after the entire first floor of the location was shut down to all unauthorized personnel.
Currently, nobody without official security clearance, is able to access the area.
The sex of Serena's first child with fiance Alexis is not currently known, however the sporting star did reveal to Vogue earlier this year that she believes she is having a daughter.
Alexis, however, is convinced that their baby will be a boy.
'Two weeks after we found out [I was pregnant], I played the Australian Open,' she recalled.
'I told Alexis it has to be a girl because there I was playing in 100-degree weather, and that baby never gave me any trouble. Ride or die. Women are tough that way.'
Serena famously won her 23rd Grand Slam at the Australian Open while pregnant, and soon after temporarily retired from competitive tennis in order to focus on the impending arrival of her baby.
It was recently revealed, however, that she is hoping to return to to the Grand Slam circuit as early as January, just in time for the Australian Open.
'That’s the goal,' her coach, Patrick Mouratoglou, told Sports Illustrated. 'It’ll depend on the date from when she can really be back working at 100 per cent.'
But while she has pulled back from competitive play, Serena has continued to keep up with her skills, regularly hitting the courts in Florida, where she has been living for much of her pregnancy, in order to hopefully minimize the amount of time before she can return to playing full-time.
According to her coach, however, Serena's original aim of returning as early as September just isn't going to happen, with Patrick telling SI.com that his player was 'dreaming' about achieving that goal.
He added that neither of them are sure what shape Serena will be in after the birth, nor what effect pregnancy and labor will have on her body, with Patrick explaining: 'This is something new for her... we don't even know how the birth is going to go.'