Uterus didelphys, also known as a double uterus, is a condition where a woman is born with two uterus, to separate cervixes and sometimes two vaginas, though this is not always the case.
It occurs because in a female foetus, the uterus starts out as two small tubes.
As the foetus develops, the tubes normally join to create one larger, hollow organ — the uterus.
Sometimes the tubes don’t join completely and each one develops into a separate hollow organ so the woman is born with two wombs.
It often only becomes noticeable after puberty and is diagnosed with a physical exam or an ultrasound scan.
In terms of physical anatomy, the two wombs are often slightly smaller than average in order to fit, though they can be as big as a ‘normal’ womb.
It also makes it possible to be pregnant twice at the same time – with a baby in each womb.
Some women are also born with two vaginas, although they can have sex and menstruate in the same way as people with just one.
‘They may know they have two and be able to find them, or they may not realise,’ Dr Leila Hanna, a consultant gynaecologist Obstetrician at BMI The Sloane Hospital, told MailOnline.
‘It can be painful because there are two squashed in the same area, so sometimes we do an operation to join them together, but its not necessary.
‘They could also have abnormalities of their kidneys and the tube which bring the urine from the bladder.’
Women will frequently have a slightly higher risk of late miscarriage, premature delivery and bleeding during pregnancy.
Often Caesarean sections are recommended, to reduce the risk of complications.
There is no treatment or cure for the condition.