Jessica Ennis-Hill has put her career on hold after announcing she is expecting her first child.
The 27-year-old confirmed that she will miss the Commonwealth Games in Glasgow this summer, although she hopes to defend her Olympic heptathlon title in Rio in 2016.
Ennis-Hill admitted the news was "very unexpected", but she and husband Andy are excited by the prospect of becoming parents for the first time.
"I have some very unexpected but exciting news to share - Andy and I are expecting a baby," said Ennis-Hill.
"We are completely overwhelmed, with excitement and a degree of anxiety that I am sure all first time parents will relate to.
"My plans for 2014 have been completely turned upside down, but having had a couple of weeks to think about things from a career point of view I am 100% set on returning to full time athletics once our baby is born and go for a second gold medal at the Rio Olympics in 2016 - that challenge really excites me.
"But in the short term I will make our baby a priority and enjoy the whole experience as much as possible.
"I am sorry I won't be in Glasgow for the Commonwealth Games, but know it will be an amazing occasion. I will be at home awaiting the arrival of a little Ennis-Hill."
Ennis-Hill endured a disappointing 2013 campaign as she struggled to recover from an ankle injury in June.
She missed the British Championships before returning to action at Loughborough, where she set a personal best in the javelin while also competing in the long jump despite still feeling pain in her ankle.
Ennis-Hill also featured in the London Anniversary Games, but she withdrew from the World Championships in Moscow four days later after revealing her ankle needed more time to recover.
Her fellow British athlete Louise Hazel, the 2010 Commonwealth heptathlon champion, believes it could be difficult for Ennis-Hill to return from becoming a mother and retain her Olympic title.
Hazel, who gave up heptathlon this year to concentrate on other events, told Sky Sports News: "Is it possible to be an elite sportswoman and have a baby? Yes. Is it possible to come back from Olympic gold as a heptathlete and go on to Rio... it throws a huge question over the continuation of a career as a heptathlete and that's just being realistic.
"I think she'll be able to come back and compete. The question is: in what event? Will she be able to get back to the same form she's been showing in recent years and be competitive?"
However, Ennis-Hill's coach Toni Minichiello is adamant that the Sky Sports Living for Sport Ambassador is targeting the heptathlon rather than any single event on her return to the track.
"We'll take it a step at a time and make sure everything is put in place for her to do the hard work," he said. "There is the indoor season potentially but certainly the World Championships in Beijing in 2015 will be the aim.
"She'll have to do a heptathlon before that in order to qualify. Getting her fit for May, that will be the primary focus, with the possibility of an indoor season before that."
Sky Sports' critically-acclaimed Sportswomen show returns for its second series next week - Tuesday at 10.30am on Sky Sports News.