Pregnant Countdown star Rachel Riley said her unborn baby stopped kicking in the womb for two days due to stress caused by online trolls.

The mathematician has been a vocal critic of Labour and its leader Jeremy Corbyn over the anti-Semitism row that has engulfed the party.

Riley, 33, who is expecting her first child with her former Strictly star husband Pasha Kovalev, said she blocked Twitter trolls for the wellbeing of her baby.

Rachel Riley
Countdown presenter Rachel Riley has discussed the stress caused by online trolls (Ian West/PA)

Speaking on the Trolled podcast with EastEnders actress Tracy-Ann Oberman, she said:  “I was very stressed and upset for a couple of days and my baby stopped wriggling for a couple of days.

“So at that point, it’s like, ‘You know what, nah’. It’s not worth the hormones.

“I’ve now changed most of my Twitter settings as you don’t need to see them.

“They’re not after proper debate. They’re not after their minds changing. They’re not doing it for virtuous reasons, so I block them.”

Riley, who announced she was pregnant in May, said the abuse intensified in July after she endorsed a BBC Panorama documentary critical of Labour’s handling of anti-Semitism complaints.

“Being pregnant has highlighted that for me: I don’t need this”, she said.

Riley has joined stars including ex-England striker Gary Lineker in a campaign to stamp out online trolling.

The group of high-profile celebrities pledged not to publicise any abuse they receive in an attempt to starve trolls of attention.

Riley, an Oxford maths graduate, rose to fame after replacing Carol Vorderman on Countdown in 2009.