Unicornuate Uterus

A unicornuate uterus is a rare condition that causes you to be born with only half a uterus.

Most women are born with one uterus, two fallopian tubes and two ovaries. The fallopian tubes extend from the top of your uterus on each side. Each fallopian tube connects to one ovary. Together, they give the uterus a shape that almost looks like a bull with two horns.

If you have a unicornuate uterus, only one side of your uterus fully develops. This means there’s just one fallopian tube and often a smaller uterus. Most people with a unicornuate uterus still have two ovaries.

Occasionally, a small piece of tissue called a rudimentary horn forms on the undeveloped side.

Symptoms of a unicornuate uterus

You may never know you have a unicornuate uterus until you’re pregnant or have trouble getting pregnant. If you have symptoms, it’s usually because you have a rudimentary horn (uterine tissue).

If your rudimentary horn is connected to your uterus, you may never have any symptoms. That’s because menstrual blood can flow out normally through your vagina. But you can have symptoms if the horn isn’t connected and it has endometrial lining (the lining you shed during your period). In that case, the menstrual blood has nowhere to go, so it builds up inside the horn.

You could have symptoms like:

• Severe pain during menstruation
• Frequent pelvic pain
• Irregular periods
• Pain from blood being trapped in your rudimentary horn

Unicornuate uterus causes

A unicornuate uterus develops before birth when your reproductive organs are forming. It occurs when the two Müllerian ducts don’t fuse together. One duct develops into the smaller unicornuate uterus and the other duct is reabsorbed by your body. In a typical uterus, both ducts join completely to create one larger cavity. Healthcare providers don’t know why the ducts don’t join correctly for some people.

Are there health risks associated with a unicornuate uterus?

There’s a link between renal agenesis and a unicornuate uterus. This usually happens on the same side as the rudimentary horn. Researchers aren’t sure why this happens.

Having a unicornuate uterus also puts you at higher risk for endometriosis if you have a blocked rudimentary horn.

How doctors diagnose unicornuate uterus

A diagnosis starts with a physical exam and a discussion of your medical history. Typically, this includes a pelvic exam. A unicornuate uterus is usually found only when you experience problems like repeat miscarriages, infertility or painful periods.

Your healthcare provider will use imaging tests, like ultrasound, MRI or hysterosalpingogram (HSG), to diagnose unicornuate uterus. These can show the size and shape of your uterus and rudimentary horn. Pelvic ultrasounds and MRI may also be able to show if there are any obstructions in your reproductive tract.

How is unicornuate uterus treated?

Generally, no treatment is necessary for a unicornuate uterus.

But if you have an associated rudimentary horn, surgery may be needed if the functioning lining in this horn is causing pain. The goal of surgery is to remove the rudimentary horn to help relieve pain and, in some cases, prevent a pregnancy in the rudimentary horn.

When should I see my healthcare provider?

Contact your healthcare provider if you have symptoms like:

• Severe pain during menstruation
• Frequent pelvic pain
• Inability to get pregnant after six months to one year of trying

Can you have a baby with a unicornuate uterus?

Yes, but you’re at risk for complications. For this reason, your healthcare provider will monitor you more closely. You’ll likely have more appointments and more ultrasounds than usual.

What are the pregnancy complications?

If you get pregnant in your rudimentary horn, it can be life-threatening. Talk to your healthcare provider about the risks of pregnancy and how yours could be affected.

If you have a unicornuate uterus, you’ll have a higher risk of:

• Miscarriage
• Stillbirth
• Preterm birth
• C-section delivery
• Breech position
• Ectopic pregnancy
• Heavy vaginal bleeding
• Placental problems, like placenta previa or placental abruption

How will it affect my delivery?

If you have a unicornuate uterus, you’re more likely to have a C-section. This is because the fetus is likely to be in a breech position due to a lack of space in your uterus.