Woman conceives twins 28 days apart after getting pregnant twice in one month

The incredibly rare phenomenon is known as superfetation.

Sophie Small fell pregnant while already pregnant and gave birth to twins conceived a month apart. (Kennedy News and Media)
Sophie Small fell pregnant while already pregnant and gave birth to twins conceived a month apart. (Kennedy News and Media)

A mum was overjoyed to discover she was pregnant while she was already expecting, after conceiving her twins 28 days apart.

Sophie Small, 30, a swimming instructor from Leominster, Herefordshire welcomed Holly and Darcy, now two, on the same day despite them being conceived one month apart due to an incredibly rare phenomenon known as superfetation, where a new pregnancy occurs after the first one.

Sophie and her husband Jonathan, 34, an accountant who already have a son named Oscar, six, were trying for another baby when they conceived Holly after a party in December 2019.

Although Sophie had an inkling that she was already pregnant, the couple decided to keep trying just in case and conceived Darcy a month later.

Sophie pictured while pregnant with the twins. (Kennedy News and Media)
Sophie pictured while pregnant with the twins. (Kennedy News and Media)

The then mum-of-one was thrilled when she took a pregnancy test a month later and discovered it was positive, but, having suffered from extreme morning sickness, Sophie decided to go for a seven-week scan to check on the health of the baby.

The scan revealed that she was pregnant with twins but the two babies were different sizes and doctors were confused as to why.

Discovering the truth

The couple only discovered the twins weren't conceived at the same time after their birth in August 2020 when Darcy was born weighing 4lbs 2oz and her sister followed two minutes later weighing 6lbs 1oz.

Though she suspected she may be pregnant after she started suffering from headaches, Sophie says her and her husband carried on trying in case she was mistaken about her symptoms.

Sophie Small conceived Holly and Darcy, now two, one month apart due to an incredibly rare phenomenon known as superfetation. (Kennedy News and Media)
Sophie Small conceived Holly and Darcy, now two, one month apart due to an incredibly rare phenomenon known as superfetation. (Kennedy News and Media)

"After I conceived Darcy, the sickness was horrific," she explains. "I was hospitalised eight times in seven weeks and spent 120 hours on a drip.

"I was carrying two babies who were growing at different stages but at the time we didn't know that," she continues.

"They couldn't work out why I was so sick."

Watch: Married couple who beat one in 200 million odds by welcoming identical triplets have brought daughters home

At her initial scan Sophie said she was told there was something different about the pregnancy.

"I was expecting twins but one was bigger than the other," she explains. "They could tell something wasn't right.

"They had their own sacs and placentas so they could feed when they wanted to, so they couldn't work out why one twin was bigger than the other."

The twins were very different sizes at birth. (Kennedy News and Media)
The twins were very different sizes at birth. (Kennedy News and Media)

After the twins were born Sophie says there was a 35% growth difference between them, which prompted doctors to realise they had been conceived four weeks apart.

"Darcy was a 32-week baby and Holly was a 36-week baby," Sophie explains. "I said it couldn't be right, I'd never heard of it. I didn't know how it happened."

Two years on

Although their daughters are twins, the couple say they couldn't be more different, with Holly still weighing 6lbs more than her sister Darcy.

Sophie says strangers in the street are often confused when they ask how many minutes are between the girls, while others don't believe her when she says they're twins.

"They don't even look like sisters," Sophie continues. "Holly has blonde hair, big beautiful blue eyes and wants to be a princess or a jockey.

"Darcy's hair is mousey brown, she's a tomboy and wants to be a train driver when she's older.

"People are surprised when I explain that Darcy is two minutes older and four weeks younger, while Holly was born two minutes after but is four weeks older," she adds.

Holly and Darcy were conceived one month apart. (Kennedy News and Media)
Holly and Darcy were conceived one month apart. (Kennedy News and Media)

Due to how quickly she conceived her son Oscar, Sophie suspected she was "super fertile" and believes she ovulated again when she was already pregnant with Holly.

At the 29-week scan, doctors were concerned they couldn't detect movement from the smaller twin and explained they may need to induce labour.

Strangers are often confused by the twins conception. (Kennedy News and Media)
Strangers are often confused by the twins conception. (Kennedy News and Media)

Using medication they managed to halt Sophie giving birth until August when Holly was born at 36 weeks and Darcy at 32 weeks.

While Holly was born with cerebral palsy, which affects the right side of her body, Darcy's stomach lining hadn't developed properly.

The twins are now two and have started nursery. (Kennedy News and Media)
The twins are now two and have started nursery. (Kennedy News and Media)

"I had no idea what the future would hold for them when they were born," Sophie explains.

"The first eight weeks were the hardest of my life," she explains.

Now aged two, the "extremely lively" twins are thriving.

"They're still hard work, but they're very mischievous, fun-loving little girls.

"It has been difficult but we're so happy and blessed to have them."

The family pictured together. (Kennedy News and Media)
The family pictured together. (Kennedy News and Media)

What is superfetation?

According to Healthline superfetation is a phenomenon that occurs when a pregnant woman releases an egg, usually a few weeks into her pregnancy, and it is fertilised and implants in the uterus. The outcome is two separate pregnancies happening at the same time

For this rare event to occur, a series of highly unusual events must defy the norm.

  1. First, the woman’s ovaries must still release an egg even though she is already pregnant (in a normal pregnancy a woman’s body sends a message to her ovaries to stop releasing eggs).

  2. Then, the semen must actually manage to make it past the already pregnant woman’s blocked cervix.

  3. Finally, the newly fertilised egg, would still have to attach itself to the womb wall, even though there’s already a baby growing there.

Additional reporting Kennedy.