Serena Williams may have second thoughts regarding a return to the women's tour when she holds her newborn daughter in her arms, according to Billie Jean King.

Williams was revealed on Friday to have given birth to a baby girl at a clinic in Florida, having initially announced her pregnancy in April.

The 23-time grand slam winner spoke last month of an ambitious plan to defend her Australian Open title in Melbourne in January.

However, King believes the reality of motherhood may prompt Williams to have a rethink, although she concedes the lure of making more history in the sport could prove too much to resist. 

"Serena is with her baby and she says she is going to be back but you never count on it because, when they hold their baby, they might decide they don't want to do that, because Serena has already won so much," King told Omnisport, courtesy of WTA-WSJ.

"But I think she does want to come back and break records, Serena is all about records now, I can tell that in the way that she speaks.

"Margaret Court has won 62 grand slam titles. Margaret's won 24 singles titles and I think Serena would like to break that, at least break the singles record of 24 majors.

"So there is a lot of incentive if Serena wants to pay the price at 37. I think you really have to pay the price and train very hard.

"I played until I was 40. Sometimes you are playing players less than half your age, so if you double their age you're still older than they are. So you have really got to be fit."