Kim Clijsters believes Serena Williams will find it tough when attempting to return to tennis after the birth of her child.
Williams, who won her 23rd Grand Slam title at the Australian Open this year, confirmed her pregnancy in April and said she would miss the remainder of the 2017 season to give birth.
The former world number one is intending to return to the sport next year but Clijsters has her doubts on whether the American will be able to dominate like she has for so many years.
The Belgium ex-number one made the 'Mother of all Comebacks' when making a sensational return in 2009 to clinch the US Open title, just 18 months after giving birth to her first baby.
The 34-year-old, who retired at the age of 29 with four Slam titles to her name, has warned Williams there will be several challenges along the way, if she decides to make a comeback.