Serena Williams is pregnant with her first child, due in autumn.
The 23-time grand slam singles champion posted a picture showing off a prominent bump on the social media app Snapchat with the caption "20 weeks" before her representative later confirmed the news.
Here, Press Association Sport looks at some athletes who have juggled motherhood with their sporting career.
The 2012 Olympic heptathlon champion missed the Commonwealth Games in 2014 as she gave birth to her son Reggie. She returned the following year and won a world title before adding Olympic silver to her collection in Rio before retiring.
Pavey produced an inspirational performance to become the oldest female European champion in 2014 at the age of 40, winning 10,000 metres gold in front of her 11-month-old daughter. Just 10 days earlier, the four-time Olympian put on one of the displays of the Commonwealth Games to secure bronze in the 5,000m. In Rio, aged 42, she became the first British track athlete to compete in five Olympics.
DAME SARAH STOREY
Storey had won 11 Paralympic gold medals when she gave birth to her daughter Louisa Marie in 2013. The following year she won four para-cycling world titles before she became Britain's most successful female Paralympian by adding another three golds to her collection in Rio.
The Belgian's professional tennis career appeared to be over, having been forced to retire at the age of 23 through injury and after giving birth to daughter Jada. However, Clijsters completed a remarkable sporting comeback to win the 2009 US Open just 18 months after giving birth - the first mother to win a Grand Slam since 1980.
The former BBC Sports Personality of the Year winner celebrated a victorious return to running after the birth of daughter Isla in 2007. Radcliffe went on to win the New York Marathon less than 10 months later, before doing so again in 2008.
This mother-of-three was part of the England squad that captured the nation's heart by finishing third at the 2015 World Cup. The midfielder had retired from international football in 2011 after becoming disillusioned by the Football Association's perceived lack of support.
Just 11 weeks after giving birth to her second daughter in 2009 she became the first Scot to win a women's major golf championship. Matthew secured a three-stroke triumph at the British Open, becoming just the third mother to have won a major since 1960.