A mum has revealed how her twins, who were born two minutes apart, actually have an age gap of four weeks between them – yes, you read that correctly.
Sophie Small, 30, from Leominster, experienced something called superfetation, a rare event that involves getting pregnant a second time, while already pregnant.
In other words, another egg is fertilised by sperm and implanted in the womb days or even weeks later than the first one.
Small told The Sun she initially thought she might be pregnant because she was experiencing headaches, but wasn’t 100% sure, so she and her partner kept on trying to conceive.
She started experiencing terrible sickness around the time of her second baby’s conception, which left her hospitalised eight times in seven weeks.
When she had an ultrasound at seven weeks, sonographers were shocked to find she was expecting twins – but that one was much bigger than the other.
“They had their own sacs and placentas so they could feed when they wanted to,” she said. “They couldn’t work out why one twin was bigger than the other.”
The babies ended up being born two minutes apart – one weighed 4lb 2oz, while the other was 6lb 1oz. It was then that doctors realised they must’ve been conceived four weeks apart.
Small, whose twins are now two, and who also has a six-year-old, said: “People think I’m a nutter when I explain, ‘Darcy is two minutes older and four weeks younger’. Some people question whether they are twins.”
She’s not alone in her experience of superfetation. While incredibly rare, in 2021 it was reported that Rebecca Roberts, then 39 and from Wiltshire, had delivered twins conceived three weeks apart – one weighed 4lb 10oz, while the other was 2lb 7oz.
The chances of experiencing superfetation are super rare, because in order for it to happen, three events need to take place, according to Healthline.
Firstly, ovulation needs to occur during an ongoing pregnancy, which is unlikely because pregnancy hormones tend to prevent further ovulation.
But “there are cases of women ovulating twice in the same cycle, or women who have ovulated while already pregnant,” Mary Jane Minkin, an ob-gyn at the Yale University School of Medicine, told Women’s Health.
Secondly, the second egg that’s released will obviously need to be fertilised by more sperm. This is unlikely to occur because once someone is pregnant, the cervix will form a “mucus plug” which prevents sperm from entering.
And lastly, the egg – now fertilised – then needs to implant in the womb, which again requires certain hormones that aren’t usually there if someone is already pregnant.
If you’re worried about superfetation, you can decrease your chances of a double pregnancy by not having sex after you’ve already become pregnant.