Edith Bowman has revealed how her heart condition meant she discovered she had lost a twin during her first pregnancy.
The radio and TV host told how her pregnancy with 12-year-old son Rudy could have resulted in two babies.
Edith was diagnosed with a bicuspid aortic valve in 2004, a condition which affects blood flow in the heart.
The former Radio 1 presenter was sent for an early scan which initially revealed there were two embryos instead of one.
Edith, of Anstruther, Fife, said a later examination detected a single heartbeat.
The 47-year-old, who has sons Rudy and Spike, seven, with Editors frontman husband Tom Smith, says the couple have been open with their eldest son about the loss.
She said: “I’ve got this heart thing. I’ve got a heart murmur – it means I’ve got a bicuspid valve rather than a tricuspid valve.
“So my doctor was like, ‘I just need you to go for an early scan much earlier than you would normally go.’
“Rudy was a double pregnancy but they said really early on that his heartbeat was really strong and the other one’s was quite weak and they were like, ‘It’s very unlikely this one is going to survive.’

“The nurse was amazing. She said, ‘You wouldn’t believe the amount of pregnancies that actually start off as twin pregnancies but because most people don’t come for scans this early they would never know.’
“I would never have known as there were no clear signs I’d lost, well, it wasn’t really a baby it was so early, to be honest.
“We’ve told Rudy about it and we’ve joked about it being like Danny DeVito and Arnold Schwarzenegger from the film Twins.
“It was quite quick from being told that to then going for the next scan and going, ‘Yeah, there is just one heartbeat.’
“Then it’s just being excited and trying to work out what you do until this thing arrives, hopefully healthy.”
Speaking on the Happy Mum, Happy Baby Podcast, with Giovanna Fletcher, Edith went on to say she had hosted
Glastonbury in 2008 only 10 days after having a caesarean section with Rudy.
She told how doctors advised her to opt for a C-section as natural childbirth would put her heart under unnecessary strain.
But she says she has felt judged by some after revealing she delivered her sons by C-section. She added: “My doctor made the decision for me. He said, ‘One of the things that puts your heart under the most strain is natural childbirth so I’d feel more comfortable that you have a C-section.’
“There is a massive stigma. I’ve experienced it whenever the person you’re talking to discovers that you’ve had a C-section. I’ve had two actually and they go, ‘Ohhhh.’ You’re like, ‘You don’t know my situation or why that decision was made.’”