A mum was overjoyed when she found she had fallen pregnant when she was already expecting, as she conceived her twins 28 days apart.
Sophie Small and husband Jonathan were stumped when their children, Darcy and Holly, were different weights when they were born at 4lbs 2oz and 6lbs 1oz.
Doctors had been confused during scans as they also showed the children were different sizes before the penny finally dropped.
Sophie, 30, had conceived Holly and Darcy, now two, one month apart due to a rare phenomenon known as superfetation, where a new pregnancy occurs after the first one.
Sophie, from Leominster, Herefordshire, said: “I was carrying two babies who were growing at different stages but we didn't know that.
"They couldn't work out why I was so sick. I had a scan at seven weeks and they said it was a bit different.
"I was expecting twins but one was bigger than the other. They could tell something wasn't right.
"They had their own sacs and placentas so they could feed when they wanted to. They couldn't work out why one twin was bigger than the other.
"When they were born there was a 35 per cent growth difference between the two of them, which is massive and they [the staff] realised they'd been conceived four weeks apart.
"Darcy was a 32-week baby and Holly was a 36-week baby. I said it couldn't be right, I'd never heard of it. I didn't know how it happened."
She says although the tots are twins, they couldn't be more different as blonde-haired Holly dreams of being a princess while tomboy Darcy has aspirations to be a train driver.
The mum says she likes to confuse strangers in the street who stop to ask how many minutes are between the girls, while others don't believe her when she says they're twins.
Sophie said: "I'm very fertile. There was no need to try, it was one attempt with Oscar.
"At 29 weeks there was another scan. They said the smaller twin wasn't moving and they couldn't find a heartbeat. I couldn't take it in. They said I possibly needed to give birth.
"I was distraught. I was given a pill to keep them in for longer. When I gave birth doctors thought they were similar sizes but there ended up being a 35 per cent difference. There's still 6lbs between them now.
"It was extremely difficult during the birth. It was covid as well so we didn't have any family or support around us.
"We had two little ones in and out of hospital going to different appointments.
"The first eight weeks were the hardest of my life. They're still hard work. They're very mischievous, fun-loving little girls.
"They're absolutely thriving. They've started nursery and they're very confident.
"They're extremely active and lively. I had no idea what the future would hold for them when they were born.
"It was so difficult but we're so happy and blessed to have them."
