Abnormalities of the uterus in pregnancy

What happens if I have uterus problems?

Sometimes, the uterus develops into an unusual shape, called a “uterine abnormality”, or “abnormality of the uterus”. You can’t prevent it, and most women won’t know they have one until they get pregnant. Try not to worry: words like ‘abnormality’ can sound frightening, but finding out more should help put your mind at rest. Your midwife and doctors will have seen similar cases, and will monitor your pregnancy closely

At a glance

  • Abnormalities of the Uterus and their side effects

What is your uterus?

Also commonly called a womb, a uterus looks a bit like an upside down pear, and it’s about the same size. It’s low down, in the middle of your pelvis, above and behind your bladder.

What does the uterus do?

As oestrogen increases every month, the lining of the uterus thickens, to get ready to nourish the fertilised egg. If you are not pregnant, this lining comes away, in the form of your period. If you are pregnant, the fertilised egg will attach to the uterus and start growing into a baby.

How does the uterus change?

As your baby grows, so does your uterus – a bit like blowing up a balloon. As it’s pretty cramped inside your body, the only way is up. By the time you’re half way through your pregnancy, it should be about the same height as your belly button. As you’re getting close to your due date, it will be almost as high as your rib cage… and the size of a watermelon. No wonder it can get hard to breathe deeply near your due date!

What if there is a problem with my uterus?

Sometimes, the uterus develops into a different shape from the normal pear-shape.  Having an abnormal uterus shouldn’t affect your chances of getting pregnant, but unfortunately, the risk of having a miscarriage is slightly higher, and you may need a C-section to deliver your baby.

What are the different types of uterus abnormalities?

These are the types of abnormalities, starting with the most common, and ending with the most rare.

Anteverted or retroverted uterus

Also called a “tipped uterus”, this is where it tilts forwards, towards your bladder (anteverted), or backwards towards your spine (retroverted). Don’t worry if you have either of these; most women do, and they don’t lead to any side effects during pregnancy. 

Arcuate uterus

This is a very common abnormality, where there is small indentation or dip at the top. Otherwise, it looks the same as a normal uterus, and does not usually cause any problems during pregnancy.

Septate uterus

Here, a muscular barrier called the septum divides the uterus. It may reach as far as the cervix (complete septate uterus) or, more commonly, just part way down (partial septate uterus). This condition may make it more difficult for you to conceive.

Bicornuate uterus

Bicornuate means “two horns”, as this is what it looks like, with a deep dip at the top. Sometimes, this is called a heart-shaped uterus.

One Bounty mum told us she has a bicornuate uterus, but it hasn’t stopped her from having six babies:

“I have a bicornuate uterus. I’ve had six children, the first five born at 42 weeks, with no problems at all. My sixth was induced as baby was small, but still fine, so try not to worry.”

Uterus didelphys

In this rare abnormality, the uterus is divided into two, and each may lead to its own cervix and vagina. Bounty mum twin wombs has uterus didelphys, and says she was worried at first, but everything turned out well in the end.

“My story is positive – I conceived within three months, didn't try that much either, and carried in my right hand womb. My baby was born two days overdue and a healthy boy of 7lb! I still worry about my second pregnancy which we are planning later this year - if it does fall in the left hand womb it could cause problems or miscarriage.”

What is a unicornuate uterus?

Unicornuate means “one horn” as there is only one fallopian tube. This rare abnormality means the uterus is about half the normal size.

Will having an abnormal uterus stop me from getting pregnant?

We are all different, so the best person to talk to is your midwife or doctor. But generally, you should be able to have a baby, although you may need extra monitoring. Because many women have them without even knowing, it’s hard to say how many cases there are, but they are fairly common. 

Women with a bicornuate uterus generally have no issues with conception or early pregnancy, however there is a slightly higher risk of miscarriage and preterm birth and this can affect the way the baby lies in later in pregnancy which can often lead to a caesarean section.

A unicornuate uterus is rare. There is an increased risk of ectopic pregnancy, late miscarriage or preterm birth and how the baby lies may be affected and could lead to a caesarean section. There is a higher prevalence of unicornuate uterus in women who are infertile.

Women with didelphic (double) uterus generally have no extra difficulties with conception and it is only linked to a small increased risk in premature birth. 

Women with subsepstate or septate wombs are more likely to have difficulties in conception. There is also an increased risk of first-trimester miscarriage and preterm birth. In later pregnancy the way the baby lies may be affected and could lead to a caesarean section.

An arcuate womb does not increase the risk of preterm birth or first trimester miscarriage but is associated with second trimester miscarriage and the way the baby lies could be affected leading to caesarean section birth. 

How will an abnormal uterus affect my pregnancy?

Of course it depends on the extent of your abnormality, but sadly, there is a higher chance of miscarriage. You’re also more at risk of other complications during your pregnancy and the birth.

Because the uterus is an unusual shape, your baby might get into a breech or transverse position, and if this happens, you’ll be advised to have a planned cesarean.

As your uterus is probably smaller than average, your baby may run out of space. This means your waters could break before you get to full term, leading to premature labour. If your baby makes an early appearance, they may need extra care.

If your cervix isn’t strong enough, known as having an “incompetent cervix”, it may not be tough enough to keep your baby inside. This could lead to premature labour, and in some cases, a late miscarriage. The risk reduces with each successful pregnancy you have.

Is there anything I can do to help?

It’s easier said than done, but try not to worry. The best things you can do are relax and stay calm. Going to all of your antenatal appointments is really important, so that your midwife and doctor can monitor you and you baby as closely as possible.

It’s also a good idea to get familiar with the signs of labour, so that you spot the signs if you get them unexpectedly early. If you’re worried, speak to your midwife or call your labour ward – it’s always better to get checked, even if it’s a false alarm.

At a glance

  • Abnormalities of the Uterus and their side effects

Abnormalities of the uterus in pregnancy