Congenital uterine abnormalities (differently-shaped womb)

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What are congenital uterine abnormalities?

What causes congenital uterine abnormalities?

How common are congenital uterine abnormalities?

Does having a congenital uterine abnormality cause problems with getting pregnant and having a baby?

How will I know if I have a congenital uterine abnormality?

What are the different types of congenital uterine abnormality?

What treatment will I have?

How can I cope during my pregnancy?

What are congenital uterine abnormalities?

Some people have a womb (uterus) that is different in shape or size from what is typical. This is called a congenital uterine abnormality (CUA). 

What causes congenital uterine abnormalities?

This is something that happens when you are a baby developing in the womb. Instead of the womb developing as two separate halves which then fuse together before birth, something goes wrong with that process.

How common are congenital uterine abnormalities?

Between 5 and 10 in 100 women and birthing people have a CUA. This is higher in people who have had recurrent miscarriage (17 in 100) and those with a history of miscarriage and infertility (25 in 100).

Does having a congenital uterine abnormality cause problems with getting pregnant and having a baby?

For many people, it doesn’t cause problems with getting pregnant and going on to have a baby.

But a CUA increases the risk of:

Reading about these increased risks may be scary but try to remember that many people with a CUA do get pregnant and have healthy babies. Your healthcare team will be able to support you throughout your pregnancy to help reduce any risks. 

How will I know if I have a congenital uterine abnormality?

Many people have a differently shaped womb but don’t know about it. Often there are no symptoms, although some people with a CUA have painful periods.

You may find out you have a CUA if you are having investigations for problems with getting pregnant or miscarriage. A routine pregnancy scan may suggest you have a CUA, but it is usually diagnosed through a three-dimensional transvaginal ultrasound scan. You might also have other investigations such as an MRI scan, laparoscopy or hysteroscopy.

What are the different types of congenital uterine abnormality?

This is a typical uterus:

Diagram of a typical uterus

Bicornuate uterus (bicornuate womb or heart-shaped womb)

A bicornuate uterus has a deep dip. It’s sometimes called a heart-shaped womb or heart-shaped uterus. If you have a bicornuate uterus, this should not cause you problems with getting pregnant or in early pregnancy, but there is a slightly higher risk of miscarriage and preterm birth. It can also affect your baby’s position later in the pregnancy so a c-section (caesarean) might be recommended.

Diagram of bicornuate uterus to illustration information in text

Unicornuate uterus (unicornuate womb)

A unicornuate uterus has only developed on one side and is usually linked to one fallopian tube and one ovary. It’s sometimes called a banana-shaped uterus. If you have a unicornuate uterus it may be more difficult for you to get pregnant.

There is an increased risk of ectopic pregnancy (where an embryo implants and develops outside the womb), late miscarriage or preterm birth. Your baby may lie in an awkward position in later pregnancy so you may be advised to have a c-section (caesarean).

Diagram of unicornuate uterus to illustration information in text

 

Didelphic uterus (didelphic womb or double womb)

The didelphic uterus, or double womb, is split in two, with each side having its own chamber, with or without its own cervix. Some people with a double womb also have a double vagina.

If you have a didelphic uterus this should not cause you problems with getting pregnant, but there is a slightly increased risk of preterm birth.

Diagram of didelphic uterus to illustration information in text

Septate uterus (septate womb) or subseptate uterus (subseptate womb)

A septate uterus has a wall of muscle coming down the centre splitting the space in two. Sometimes the wall only comes part-way down the womb (subseptate) and other times it comes the whole way down (septate).  

If you have a septate or subseptate uterus you are more likely to have difficulties with getting pregnant. There is also an increased risk of early miscarriage and preterm birth. In later pregnancy, your baby may not be lying in a head-down (cephalic) position so you may be advised to have a c-section.

Diagram of septate uterus to illustration information in text

“When I was first diagnosed with a septate uterus, I was petrified. I read a lot of scary information online about the risks associated with a septate uterus. My consultant reassured me that a lot of women have congenital uterine abnormalities and are not aware. I read online that a lot of women with a septate uterus have surgery to resect the septum before pregnancy. My consultant did not recommend this. Despite having a complete septate uterus, I was able to carry my baby to term. He was breech, so I did have an elective c-section. I wish I would have trusted my consultant more and not believed everything I read online.” 
Emma
 

Arcuate uterus (arcuate womb)

The arcuate uterus looks very like a typical womb but it has a shallow dip at the top.  

Having an arcuate uterus doesn’t cause problems with getting pregnant or increase your risk of preterm birth or early miscarriage, but it increases your risk of late miscarriage. In later pregnancy, your baby may not be lying head down so you may be advised to have a c-section. 

Diagram of arcuate uterus to illustration information in text

What treatment will I have?

This depends on the type of congenital uterine abnormality you have and your medical history. Surgery might be suggested if you have recurrent miscarriage, for example, or if you have part of the womb that needs removing, as happens to some people with a unicornuate uterus. For most types, it’s unclear whether surgery is helpful, and there are associated risks.  

Your healthcare professional should discuss treatment options with you. If a womb abnormality is identified before a pregnancy, this is likely to be a gynaecologist. If you are diagnosed during pregnancy, you’ll be cared for by the obstetric team. You will also be offered extra scans and hospital visits to check up on you and your baby throughout the pregnancy.  

If your baby ends up in an awkward position (lying across your womb or bottom first) in later pregnancy, your healthcare team will talk to you about your birth options.  

How can I cope during my pregnancy?

If you know you have a congenital uterine abnormality, you may feel anxious during your pregnancy, especially if you’ve previously had a miscarriage or premature baby. We have information on mental health and wellbeing, including where you can look for support. Your healthcare team can also talk to you about available support.

It’s important to go to all your antenatal appointments so you can have the relevant tests and scans. If you feel something is wrong, contact your maternity unit straight away. Don’t worry that you may be wasting anyone's time. Your maternity team would rather make sure that you and your baby are safe.  

If you have any concerns or questions, you can also talk to a Tommy’s midwife for free from 9am–5pm, Monday to Friday on 0800 0147 800 or email them at [email protected]. Tommy’s Midwives also run a specialist Black and Black-Mixed Heritage Helpline too – you can book a call with them.

It's also good to know the signs of preterm labour, if you think your baby is coming too soon.  

 

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Review dates
Reviewed: 15 January 2025
Next review: 15 January 2028