The case of a woman who discovered she had two wombs and was pregnant with a twin in each has been described as “one in 50m” by doctors.

Kelly Fairhurst, 28, only learned she had uterus didelphys, a condition where a woman has two wombs, when she went for her 12-week scan. She was also told she was carrying twins, one in each womb.

“The twins could be identical. The condition itself is quite rare but they went on to tell me that it was a one in a 50m chance for me to conceive twins in each womb,” she told the Sun.

Fairhurst, who was also surprised to be told she had two cervixes, already has two daughters, aged three and four. “With my second baby they said that I might have a bicornuate uterus, which means it’s not fully formed. So when I went for this scan, I was really surprised to learn that I have two of them.

“I just thought, ‘God, that’s a shock.’ It makes you feel incredibly grateful that this has happened to you and you get to have two amazing babies.”

Doctors have told Fairhurst, who lives in Braintree, Essex, that she might have two separate labours and the plan is for her to have both of the babies by cesarean section.

Prof Asma Khalil, an expert in obstetrics at St George’s hospital in London, said uterus didelphys was very rare. “A lot of women who have abnormalities in the uterus don’t know,” said Khalil. She added this was even the case with women who had had babies because the shape of the womb changed during pregnancy and so the condition could be missed in scans.

Khalil said it was possible that Fairhurst was carrying identical twins, each developing in a separate womb. “It can happen. The egg and sperm, at a very early stage, they split into two, so it depends which egg attaches to which uterus.”