Unicornuate Uterus

Unicornuate uterus is a rare genetic condition in which only one half of a girl’s uterus forms.

A unicornuate uterus is smaller than a typical uterus and has only one fallopian tube. This results in a shape often referred to as “a uterus with one horn” or a “single-horned uterus.”

Women with a unicornuate uterus may also have a second smaller piece of a uterus, called a hemi-uterus.  This hemi-uterus may not be connected to the rest of the uterus. As a result, menstrual blood is unable to flow out of this hemi-uterus, causing pain.

Patients can be seen by Texas Children's experts in Pediatric and Adolescent Gynecology.

Causes & Risk Factors

A unicornuate uterus occurs when the uterus doesn't form properly during fetal development. Normally, two tubes join together to create the uterus. When one of these tubes fails to develop, the result is a unicornuate uterus.

The cause of this abnormal fetal development is not yet known.

Symptoms & Types

Symptoms may include:

  • Abdominal pain if other uterine remnants are found
  • Difficulty getting pregnant
  • Complications during pregnancy and/or delivery, including preterm labor, miscarriage and breech delivery (feet first)

Diagnosis & Tests

The condition may go undetected until a young woman has difficulty getting pregnant or experiences complications during pregnancy.

Diagnosis starts with a thorough medical history and physical exam, including a pelvic exam.

Additional testing may include:

  • Imaging – such as ultrasound, magnetic resonance imaging (MRI) or laparoscopy to look for uterine abnormalities
  • Hysteroscopy – uses a tiny telescope, called a hysteroscope, inserted through the vagina into the uterus to view and treat areas of concern 

Treatment & Care

Treatment strategies include:

  • Laparoscopic surgery to remove a non-connected hemi-uterus that results in abdominal pain due to inability of menstrual blood to flow to the main uterus.
  • Specialized care during pregnancy/delivery to reduce the risk of complications, including preterm delivery, miscarriages or breech births (feet first).