What does a normal womb look like?
The womb (uterus) is shaped a bit like an upside-down pear, tucked away in the pelvis. It's about 7.5cm long, 4.5cm wide and 3cm deep
(Parmar et al 2016). If you've had a baby before, your womb is likely to be slightly bigger than this
(Parmar et al 2016, Verguts et al 2013).
The womb usually leans forwards, towards the tummy. Doctors call this position anteverted or anteflexed
(Behera 2015).
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It’s very common to have a womb that tilts backwards, towards the spine, instead. This is known as a
tilted uterus (retroverted uterus) (Fidan et al 2017, O'Grady 2015).
A tilted uterus isn't considered an abnormality, because it only affects the position of the womb, not how well it works
(O'Grady 2015, Whelan 2019). Having a tilted uterus won't affect your chances of getting pregnant
(O'Grady 2015). However, it can sometimes be a sign of another underlying condition, such as endometriosis, that could affect your fertility
(Whelan 2019).
Another common and normal womb shape is an arcuate uterus
(Ahktar et al 2019, Laufer and DeCherney 2019). This is where your womb has a dip, or a slight indentation at the top
(Laufer and DeCherney 2019). Having an arcuate uterus should not affect your ability to get pregnant or lead to pregnancy complications
(Ahktar et al 2019, Laufer and DeCherney 2019, Vaz et al 2019).
What is an abnormal womb?
An abnormality of the womb, or uterine abnormality, is the term doctors use for a womb with an unusual shape.
It may sound scary, but it’s actually common; studies suggest that at least one woman in 18 has some type of uterine abnormality
(Laufer and DeCherney 2019, Vaz et al 2017). It's hard to be sure about the numbers because uterine abnormalities don’t always cause problems, so they’re not always diagnosed.
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It's thought that about one in 13 women with fertility issues has a uterine abnormality
(Laufer and DeCherney 2019, Vaz et al 2017). The rates are higher in those with a history of miscarriage, with around one in eight thought to be affected
(Laufer and DeCherney 2019, Vaz et al 2017).
Will I be able to get pregnant if I have an abnormal womb?
Uterine abnormalities don't usually affect fertility
(Ahktar et al 2019, Laufer and DeCherney 2019, Tidy 2016). However, it depends on the type of abnormality you have
(Ahktar et al 2019, Laufer and DeChenery 2019a). If it's a minor abnormality, you may not even realise you have it, until you have happen to have an ultrasound for some reason
(Ahktar et al 2019).
Some types of uterine abnormality may increase the risk of
complications during your pregnancy, such as giving birth prematurely
(Ahktar et al 2019, Laufer and DeCherney 2019). However, if this is the case for you, your midwife and doctor will monitor you closely throughout your pregnancy, to make sure that you and your baby are well.
Here are the main types of uterine abnormality, with pictures to help illustrate how the womb may look:
Septate uterus This is where the inside of your womb is divided by a muscular wall, called a septum. It’s the most common uterine abnormality
(Laufer and DeCherney 2019). About one woman in 45 has a septate uterus
(Chan et al 2011a, ASRM 2016). The septum may extend only part of the way into your womb (subseptate or partial septate uterus) or it may reach as far as your cervix (complete septate uterus). A septate uterus may make it more difficult for you to conceive and, sadly, may increase your risk of miscarriage
(Ahktar et al 2019, Laufer and DeChenery 2019a).
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Bicornuate uterus This is where you have two wombs that join into a single cervix, with a single vagina
(Laufer and DeCherney 2019, Vaz et al 2015). Instead of being pear-shaped, this type of uterus is shaped like a heart, with a deep indentation at the top. It's also known as a "uterus with two horns", because of its shape. Around one in every 250 women have a bicornuate uterus
(Chan et al 2011a). It shouldn't affect your ability to get pregnant, but you do have a higher risk of pregnancy complications
(Ahktar et al 2019, Laufer and DeChenery 2019a). Sadly, there’s also a higher risk of miscarriage
(Ahktar et al 2019, Laufer and DeChenery 2019a).
Uterus didelphys This is when you have two wombs, each with its own cervix
(Laufer and DeCherney 2019, Vaz et al 2015). It's an uncommon abnormality, affecting about one in 350 women
(Chan et al 2011a). In some cases, there may also be two vaginas
(Laufer and DeCherney 2019). This type of abnormality is unlikely to affect your fertility but it is linked with pregnancy complications, such as
breech and premature labour
(Ahktar et al 2019, Laufer and DeChenery 2019a).
Unicornuate uterus A unicornuate uterus is half the size of a normal uterus and there is only one fully-developed fallopian tube
(Amesse 2018). Because of its shape, it's sometimes described as a uterus with one horn. A unicornuate uterus is rare, affecting about one in 1,000 women
(Chan et al 2011a). You should still be able to get pregnant if you have a unicornuate uterus. However, it does put you at greater risk of pregnancy complications, and miscarriage
(Ahktar e tal 2019, Amesse 2016, Laufer and DeChenery 2019a).
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Agenesis This is a much rarer condition, where the uterus and vagina haven't formed properly, or at all
(Laufer and DeChenery 2019a). If both the uterus and vagina haven’t formed at all, it’s called Mayer Rokitansky Küster Hauser (MRKH) syndrome
(Amesse 2018), which is thought to affect around one in 5,000 women
(Amesse 2016). Agenesis is usually picked up when a girl reaches puberty, and hasn’t started her periods as normal
(Ahktar et al 2019, Amesse 2016).
Treatments for agenesis may involve the creation of a vagina
(Kirsch 2018, Saxena 2018), or the lengthening of a short vagina, making it possible for you to have sex
(Amesse 2016, Saxena 2018). If you have agenesis, you will probably still have functioning ovaries and be able to produce eggs
(Amesse 2018). This means you may still be able to have a baby through
surrogacy (Friedler et al 2016).
How will I know if I have an abnormal womb?
If you're having
fertility problems or
recurrent miscarriages, your doctor will refer you to a
specialist to see if it has anything to do with your womb or fallopian tubes
(NICE 2013, RCOG 2011).
Your specialist may recommend you have a number of procedures to help them get a picture of how well your womb and fallopian tubes are working. These could include the following:
- A special X-ray using dye, called a hysterosalpingography (Laufer and DeChenery 2019a, NICE 2013, Tidy 2016). The dye is inserted into your womb and fallopian tubes through a fine tube (catheter), then an X-ray is taken. Or your specialist may recommend an alternative test called a hysterosalpingo-contrast-ultrasonography (NICE 2013). This involves releasing bubble-filled water inside your womb, providing a clearer picture during an ultrasound.
- A minor operation called a laparoscopy and dye (Laufer and DeChenery 2019a, NHS 2020, NICE 2013). This allows your doctor to have a look at your womb and fallopian tubes. Your doctor will pass a tube with a camera (endoscope) through a small cut in your belly button, to examine you internally. This is a minor, keyhole procedure, and you will probably be able to go home the same day.
- An ultrasound scan of your womb (Akhtar et al 2019, NHS 2020, RCOG 2011, Tidy 2016). A sonographer may put some gel on your tummy and move a hand-held device (transducer) over your skin to pick up images of your womb. Or they may ask to carry out a vaginal scan to get a more detailed picture. This involves putting a sterile, narrow transducer, not much wider than a finger, into your vagina (NHS 2018a). It shouldn’t hurt but it may be uncomfortable.
- A magnetic resonance imaging (MRI) scan (Ahktar et al 2019, Laufer and DeChenery 2019a, Tidy 2016). A radiographer carries out an MRI scan. You’ll be asked to lie on a flat bed which moves slowly through a large scanner (Krans 2018, NHS 2018). The test is completely painless (NHS 2018b), and usually takes less than an hour (Krans 2018). In some cases, your radiographer might recommend that you have an injection of a special type of dye, to help tissues and blood vessels show up more clearly (Krans 2018, NHS 2018b).
If you have a uterine abnormality that you’re not aware of, and you become pregnant, it may be picked up at your first ultrasound scan.
How are uterine abnormalities treated?
You may not need any treatment at all to conceive and have a healthy pregnancy. But if you're struggling to conceive, your treatment options will depend on what type of abnormality you have
(Ahktar et al 2019, Tidy 2016).
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The most common type of abnormality is a septate uterus. If you've experienced recurrent miscarriages with a septate uterus, your doctor may recommend a type of surgery called a metroplasty
(Ahktar et al 2019, Vaz et al 2019). This will remove the septum in your womb
(Ahktar et al 2019, NICE 2015). The procedure does carry some risks, as it could damage the lining of your womb
(Ahktar et al 2019, NICE 2015). But it may improve your chance of having a successful pregnancy
(Ahktar et al 2019, NICE 2015). Your doctor will discuss this with you and help you to weigh up the pros and cons.
If you have a unicornuate uterus, your doctor may recommend surgery to prevent an
ectopic pregnancy from developing in the future
(Ahktar et al 2019, Laufer and DeChenery 2019b).
Your doctor will only recommend surgery for other uterine abnormalities if you’ve suffered from recurrent miscarriages, and only if they think your pregnancy losses are because of the shape of your womb
(Laufer and DeChenery 2019b).
Sadly, in some cases, certain abnormalities may mean it’s not possible to conceive or carry a baby
(Ahktar et al 2019, Tidy 2016). If this is the case for you, it’s natural to feel shocked, sad and angry.
You can read more about
coping with a fertility problem, including information about counselling. When you’re ready, you can also find out more about other options for having a baby, such as
surrogacy or adoption.
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Read about
abnormalities of the womb (uterus) in pregnancy.
Images by David Browne for BabyCenter