Expectant mum Elaine Hilton and her baby are lucky to be alive today – thanks to two pet cats which alerted her to a carbon monoxide leak.
Elaine, 39, was 40 weeks pregnant when her old-fashioned boiler started leaking the lethal gas into her home in November last year.
She thought her drowsiness was down to her pregnancy until her three-year-old cats, Tinker and Bell, started crying and then collapsed, alerting her to the danger.
"I owe everything to them," she said. "They literally saved my life. My cats have been spoilt rotten since it happened and I just love them to bits."
Elaine told her local paper: 'It was a nice quiet Sunday afternoon and I was lying on the sofa watching some TV while my ex-partner was cooking in the kitchen.
"I'd put the heating on a few hours before because I was going to have a bath and soon after I started to feel funny and light-headed.
"I felt really dizzy, but I assumed it was caused by my pregnancy so I was planning to have a nap on the sofa.
"That's when my cats started crying. They were making really high-pitched whimpering sounds, almost like a baby, which was really unusual.
"At first I thought they might just be hungry but then I realised something was wrong.
"They went and hid behind the sofa, where they collapsed. It was as if they were too weak to hold up their own weight.
"One of the cats was fitting. Her eyes were rolling and her body was shaking.
"We were going to phone the vet, but they never acted like this before so alarm bells started ringing."
Elaine and her then-partner, Geoff Lilly, 53, phoned the fire brigade and carried the cats into the garden where they waited until firefighters arrived.
They took readings from inside the house in Doncaster, South Yorkshire, which showed high levels of carbon monoxide in the air, caused by soot blocking an air vent.
Elaine was rushed to Doncaster Royal Infirmary with carbon monoxide poisoning and worryingly, no one knew if her unborn baby, Amber-Louise, now four months, had been affected.
She said: "My baby was my main concern. I never thought I would ever have a child and I was terrified at the thought she might be in danger.
"The hospital said they'd never dealt with a pregnant woman suffering from carbon monoxide poisoning so they had no idea if my baby would be OK.
"The only thing they could do was monitor the baby's heartbeat. They kept me in for four days and gave me air to try and flush out the carbon monoxide from my system.
"They couldn't do anything more and I was told they would only know if my baby had been affected once she was born.
"I had to wait another two weeks until I gave birth. It was an incredibly stressful time. It was a waiting game and the whole time I was worrying about it.
"When my daughter was born they had a paediatrician on standby just in case but she was fine. She was healthy and she's been fine ever since.
"It's a miracle that my baby is perfectly healthy. It could have been a lot worse. Both of us are so lucky to be here."
Elaine is now helping the Doncaster Carbon Monoxide (CO) Partnership to raise awareness of the 'silent killer', which has no colour, taste or smell.
• After reading this story, I immediately went online and ordered a carbon monoxide detector from British Gas. It cost £29.99 – and my three children's lives are worth a lot more than that.