World No 1 Serena Williams has suggested she intends to return to tennis after the birth of her first child.

Williams posted a message on Instagram to her unborn baby in what was her first public statement since first announcing last week that she is pregnant.

“I can’t wait for you to join the players box next year," she said. "But most importantly, I am so happy to share being number one in the world with you.

Venus and Serena Williams vs the world: The inside story on the making of two titans of tennis Show all 3 1 /3 Venus and Serena Williams vs the world: The inside story on the making of two titans of tennis Venus and Serena Williams vs the world: The inside story on the making of two titans of tennis 5456270.jpg Venus and Serena celebrate winning gold in the London 2012 Olympic Games women's doubles AFP/Getty Images Venus and Serena Williams vs the world: The inside story on the making of two titans of tennis 5456269.jpg Serena and Venus in 1996, at the start of their extraordinary careers Rex Features Venus and Serena Williams vs the world: The inside story on the making of two titans of tennis 5456274.jpg Serena and Venus posing with their mother, and coach, Oracene in Florida in 1999 Getty Images

“You gave me the strength I didn’t know I had. You taught me the true meaning of serenity and peace. I can't wait to meet you.”

Williams’ baby is due later this year. The American will be 36 should she return to the sport at the start of next year.

Trainer Mackie Shilstone is confident the 23-time Grand Slam winner will “come back stronger” after the pregnancy.

“Without a doubt I think she will come back and be even strong – because she will be playing for two,” Shilstone told the Guardian last week.

“If she sets foot on the court she will come to play. I hate using the word ‘star’ but Serena is a star in the true sense. She is just unique.”

A number of tennis players have won Grand Slam titles after giving birth.

Belgium’s Kim Clijsters won the US Open in 2009 and 2011, as well as the Australian Open in 2011, after giving birth in 2008.

Williams with the Australian Open trophy earlier in the year (Getty)

Margaret Court Smith won three of her 24 titles after having a child in 1972.

Williams reclaimed the world No 1 spot on Monday without having played a single tournament since her Australian Open win in January.

Angelique Kerber can win back that ranking, though, if she wins two matches at this week’s Porsche Grand Prix in Germany.