Lizzie Kelly, the first woman to ride a Grade One winner over jumps in Britain, is halting her career as a jockey to start a family.
Kelly, 27, has announced she is expecting her first child with husband Ed and is unlikely to return competitively to the saddle.
"I will not be returning to the weighing room this season and in all likelihood not at all," she said.
She made history with a Grade One win on Tea For Two at Kempton in 2015.
Kelly, from Devon, followed up with another top-level victory on the same horse, trained by stepfather Nick Williams, at Aintree's 2017 Grand National meeting.
The previous month she had been unseated by her mount when becoming the first woman to ride in the Cheltenham Gold Cup for 33 years.
Victories at the Cheltenham Festival came aboard Coo Star Sivola and Siruh Du Lac, with hurdler Agrapart another notable partnership.
Kelly, who has been a pundit for BBC Radio 5 live at Cheltenham and Aintree, plans to stay involved in racing and has a new bloodstock business with her husband.
"I hope to continue working within the racing media, something I've always enjoyed and am passionate about," she said.
"I'll really miss race riding but won't miss those saunas. It's been a dream. Thanks to all."
Analysis - 'a breath of fresh air'
Frank Keogh, BBC Sport
Kelly has recalled how people chuckled when she stated as a schoolgirl that her ambition was to become a professional jockey.
But she had the last laugh, winning on some of the biggest stages and proving a breath of fresh air in and out of the saddle as a forthright advocate of women in the sport.
Her achievements, following on from the successes of amateur jump jockeys Nina Carberry and Katie Walsh, provided another female role model and more have followed.
Last year, Bryony Frost on Frodon became the first woman to ride a Grade One winner over jumps at the Cheltenham Festival and Rachael Blackmore was runner-up to Paul Townend in the Irish jockeys' championship.
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