When their pregnant mother Zoe collapsed unconscious at home, she didn't think there was anyone to help her. But she didn't count on the quick thinking of her son Billy who phoned for the ambulance, which ended up saving the life of his unborn sister.
Zoe was rushed to hospital, where she was given treatment and tests showed her baby was still alive. Now baby Sally has been born safely - to the relief of Billy who is thrilled with his sister's arrival.
Zoe, 31, who works as a private carer, says: "Sally is here today because of Billy's quick thinking. He saved her life.When I collapsed on the floor it was only thanks to him calling the ambulance that I was able to get to hospital so quickly, and was able to get treatment.
When Sally is older I will definitely tell her how her big brother saved her life.
Zoe, who lives with partner Mark Westmoreland, in Hartlepool, started suffering from a rare condition where her blood pressure suddenly plummets, causing her to collapse unconscious when she was six months pregnant:
"I then collapsed regularly after that, and even hit my head once, causing bruising on my face. When I went to the hospital the midwife left a leaflet for me on domestic violence as she thought it had caused the bruising."
Zoe tried to make sure she was never alone due to the condition which is called vasalvagal syncope, a loss of consciousness caused by a sudden drop in blood pressure.
But when she was 28 weeks pregnant, she was alone in the house with her son Billy, and collapsed on their living room floor.
Billy managed to get the keys and put them through the letter box so that the paramedics could unlock the front door.
"He was so brave, he just kept his head and didn't get frightened," says Zoe. "I am so proud of him. When I fall I need to get to hospital straight away. I fall onto my stomach which could have harmed the baby.
If Billy hadn't called for the ambulance I would have been left there and the baby may not have survived my fall.
Zoe was taken to North Tees Hospital in Stockton where doctors gave her oxygen treatment and monitored the baby's heartbeat. Luckily her baby had survived the fall and she was told by doctors that she needed to either remain in hospital for the remainder of her pregnancy or have constant 24 hour supervision.
"I wasn't even allowed to take Billy to school because I was collapsing so much, several times each week," explains Zoe. "It was a terrible pregnancy. When I had been pregnant with Billy, this had never happened. It was so debilitating.
Zoe was still collapsing regularly until the birth of daughter Sally in July last year, who despite all her mother's falls, arrived safely.
"I was just so thrilled when Sally was finally born and she was healthy. It is amazing considering the amount of times that I collapsed during my pregnancy," says Zoe.
Billy is on medication for epilepsy, but he managed to do so well calling for the ambulance by himself. When I arrived at the hospital the doctors couldn't believe that he had managed to do so well.
"He adores Sally and they are so close. And when she's older I will tell her how her remarkable brother saved us both."
Words: Lucy Laing at Worldwide features