Urogenital Sinus


What is a urogenital sinus?

Urogenital sinus is a defect in your baby girl’s urinary and reproductive tract that happens during early fetal development and is present at birth. Normally, for a short period of time, the intestinal, reproductive and urinary tracts of your developing baby share a common cavity and opening. As your pregnancy continues, however, these three tracts separate and each develops its own opening.

In normal female development, the urinary tract (bladder), reproductive tract (vagina) and intestinal tract (rectum) all develop separate exits out the body.

In normal development, a baby girl’s urinary tract (bladder), intestinal tract (rectum) and reproductive tract (vagina) each develop their own separate pathways and exits out the body.

When the urinary and genital tracts – specifically the urethra (“exit tube’ for urine) and vagina (“birth canal”) – continue to share a common passageway with a single opening, instead of forming their own separate openings, the condition is called urogenital sinus (also called persistent urogenital sinus). The shared passageway with a single opening is called the cloaca.

In short, if your baby girl is born with urogenital sinus, she only has two “openings,” a rectum where stool (“poop”) comes out and a common opening for both the exit of urine and the vagina.

How common urogenital sinus?

Urogenital sinus is a rare developmental defect affecting girls. The incidence rate is 0.6 per every 10,000 female births.

What are the types of urogenital sinus?

There are two types of urogenital sinus problems, “low joined” and “high joined:”

  • In “low joined” cases, the point at which the urethra and vagina join together into a single shared channel is low (closer to the opening out the body); the shared section is short. Both the urethra and vagina are relatively normal in their size and location.
  • In “high joined” cases, the point at which the urethra and vagina join together into a single shared channel is farther up the channel (farther away from the opening out of the body); the shared section is long. This is a more serious condition because more serious complications can develop. The anus can be located too far forward, as well.

Symptoms and Causes

What causes urogenital sinus?

The cause of urogenital sinus is not always known. Sometimes it involves a condition known as congenital adrenal hyperplasia (CAH), in which one or both of a person’s adrenal glands do not produce the enzyme needed for hormones to develop. This problem is seen in baby boys and girls, but girls are more likely to have unusually shaped genitals as a result.

What are the signs of urogenital sinus?

Specific defects may involve:

  • Presence of a single opening for stool to exit the body and only one other opening for both the vagina and for urine to exit.
  • Abnormal closure or absence of a vagina.
  • Lack of full development of the uterus, ovaries or fallopian tubes.
  • Variation in development of the rectum or bladder.

Diagnosis and Tests

How is urogenital sinus diagnosed?

Diagnosing urogenital sinus is an important part of deciding how to treat it. The condition can affect your child’s overall growth and development, not just the genitals.

Sometimes urogenital sinus can be diagnosed during a prenatal ultrasound. Usually it’s discovered during your baby’s first exam, shortly after she is born. Your healthcare provider will typically order blood tests to learn more about her overall health and genetic issues. The provider may call in a specialist to examine her as well.

In addition to blood work, other tests can provide more information about the extent of the urogenital sinus. These tests include:

  • Ultrasound: This is a procedure that transmits high-frequency sound waves through body tissues. The echoes are recorded and transformed into video or photographic images of the internal structures of the body. This tests shows if there are problems with the kidneys, bladder, vagina, and rectum. It also can show if there is any swelling or buildup of urine due to the birth defect.
  • Retrograde genitogram: Dye is injected into the common urethra/vagina and X-rays of the area are taken. The dye helps define the tissues and organs so that their size, shape, and location can be seen clearly.
  • Magnetic resonance imaging (MRI): An MRI is a test that uses a large magnet, radio waves, and a computer to produce very clear images of the human body without X-rays. In infants with a urogenital sinus, the doctor may order an MRI to look at the pelvis and spine to see if there are any problems in those areas, as well.
  • Endoscopy: A special type of camera is inserted into the common urethra/vagina to see the anatomy.

Management and Treatment

How is urogenital sinus treated?

The only way to treat urogenital sinus is to perform surgery to separate your baby’s vagina and urethra. For “low joined” cases, a surgeon will most often choose to perform a “flap vaginoplasty.” This procedure involves creating two separate openings from the body, one each for the vagina and urethra.

For “high joined” cases, the surgeon will usually perform a more complicated surgery called a “pull-through vaginoplasty,” in which the vagina is detached from the common opening and made into its own entity. The opening is then closed; urine will continue to empty through what had been the common opening. Another procedure is a urogenital mobilization, used in combination with a flap vaginoplasty.

Some girls may need to have a clitoroplasty and/or labiaplasty, as well. Clitoroplasty involves reshaping tissue to create a more typical clitoris. The nerves are preserved as much as possible to allow the patient to have a healthy sex life as an adult. Labiaplasty involves reshaping the tissues – the “lips” – surrounding the vagina.

Outlook / Prognosis

What can patients expect after urogenital sinus surgery?

The outcome for girls with urogenital sinus depends on the extent of the defect. The goal of surgery is to give your daughter normal function and genital appearance as much as possible. Most girls are able to urinate normally after they heal. Young women can also expect an enjoyable sex life. Women will be able to have children. If surgery was extensive, giving birth by Cesarean section may be best. This is decision that can be discuss with their doctor.

Last reviewed by a Cleveland Clinic medical professional on 07/10/2020.


  • The American Urological Association. Accessed 7/7/2020.What Are Urogenital Sinus Abnormalities? (http://www.urologyhealth.org/urologic-conditions/vaginal-abnormalities-urogenital-sinus)
  • The American Urological Association. Accessed 7/7/2020.What Are Vaginal Abnormalities: Cloacal Abnormalities? (http://www.urologyhealth.org/urologic-conditions/vaginal-abnormalities-cloacal-abnormalities)
  • Singh S, Singh P, Singh RJ. J Anat Soc India 2010;59(2):242-244. Accessed 7/7/2020.Persistent Urogenital Sinus. (https://www.researchgate.net/publication/259347226_Persistent_Urogenital_Sinus)

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