The couple's agent confirmed the pregnancy.
The Olympians rounded off their success in Rio with a personal triumph as they confirmed they have tied the knot.
Laura Trott has announced her engagement to fellow double Olympic cycling champion Jason Kenny.
The couple went public about their relationship during the London 2012 Games, where they won two gold medals apiece.
Essex-born Trott, 22, tweeted the news this morning:
Merry Christmas everyone :) ive had the most amazing couple of days thanks to @jasonkenny107 and the whole family ? ? #engaged X
Trott triumphed in the team pursuit and the six-discipline omnium at London 2012, while Kenny was victorious in the team and individual sprints.
They were also both made OBEs in the 2013 New Year Honours.
Olympic cycling hero Jason Kenny said he was "blown away" by the reception he received today as thousands of fans turned out to greet him in his home town.
Wearing his two gold medals around his neck, Kenny was accompanied by his girlfriend and fellow double gold medal-winning cyclist Laura Trott as he greeted supporters outside Bolton Town Hall.
Kenny, who is 24 and won gold in the men's team sprint and the individual sprint at London 2012, also took home gold and silver medals four years ago in Beijing.
His races were shown again on a large screen to loud cheers from the crowd assembled outside, while Kenny also attended a civic reception inside.
British gold medal winning cyclists Laura Trott and Jason Kenny were caught on camera kissing during the women's volleyball final.