OEIS Syndrome: Understanding Cloacal Exstrophy and Surgical Reconstruction

Medically reviewed by Dr. Baraa Alnahhal, MD · Last reviewed: October 2026

Quick Answer: What is OEIS syndrome (cloacal exstrophy)?

OEIS syndrome, or cloacal exstrophy, is a rare birth defect in which the lower abdominal wall does not form completely, so the bladder and part of the intestines are outside the body at birth [1]. Its cause is unknown [1]. It is usually diagnosed on prenatal ultrasound, and all affected newborns need staged surgical reconstruction over many years [1].

Key takeaways

• OEIS syndrome is a rare congenital birth defect, also called OEIS complex or cloacal exstrophy [1].

• It affects several body systems: urinary, digestive, reproductive, and the spine and nervous system [1] [2].

• The four core features are an omphalocele, exstrophy of the bladder and rectum, an imperforate anus, and spinal defects [1].

• Treatment is staged surgical reconstruction that takes place over many years as the child grows [1] [2].

• The main goals of care are to protect kidney function, keep urinary infections low, and develop strategies for managing urine and stool [1].

What the research says

• Nearly all children with cloacal exstrophy now survive, and care has shifted toward long-term quality of life. A 2024 review describes cloacal exstrophy as the most severe form of the exstrophy-epispadias complex. It notes that individualized reconstruction by a multidisciplinary team, often in stages through childhood and adolescence, has led to survival for nearly all patients. Long-term problems such as incontinence and sexual dysfunction are now recognized, and many people need complex care into adulthood (Ostertag-Hill et al., Children (Basel), 2024 [2]).

• Direct and staged bladder closure gave comparable early results in one small series. In a retrospective study of 12 children treated between 2008 and 2024 at a hospital in Mexico, 5 had direct closure (median age at surgery 9 days) and 7 had staged closure (median 62.5 days). Early outcomes were comparable with no statistically significant differences, and wound infection was the most common complication. The authors suggest single-stage closure for male newborns and a staged approach for children referred later or with low birth weight, a wide pubic gap (over 5 cm), or serious heart problems. This was a very small study from one center, so surgical choices should always be made by your child's team (Costa-Roig et al., Pediatr Surg Int, 2025 [3]).

What Is OEIS Syndrome (Cloacal Exstrophy)?

OEIS syndrome (cloacal exstrophy) is a rare congenital condition, or birth defect, that affects how the lower abdominal wall, intestines and urinary bladder form during fetal development [1]. This results in the bladder and part of the intestines being outside of the body at birth [1]. Babies with cloacal exstrophy usually have other associated abnormalities at birth, affecting other abdominal organs, the anus and rectum, the genitals, the spinal cord and the lower limbs.

It is estimated to occur in about 1 in 200,000 to 400,000 births, according to Cincinnati Children's Hospital [4]. Other names for OEIS syndrome are OEIS complex and cloacal exstrophy [1].

The name "OEIS" is an acronym for the four main conditions that occur together:

• Omphalocele: As the abdominal wall does not form as expected, there is a hole near the belly button or umbilical cord. Some of the abdominal organs come out of this hole inside a membrane or sac [1].

• Exstrophy of the bladder and rectum: The bladder opens up like a flat plate instead of a hollow sphere and may split into halves [1]. The pelvic bones do not join correctly and are far apart [1]. The rectum and colon may also be open and split in half [1]. There may be extra parts of the intestines and internal reproductive organs, and the genitals may be split and smaller than expected.

• Imperforate anus: The opening to the anus does not form. The intestines may be shorter than expected, which can affect how your body absorbs nutrients [1].

• Spinal defects: As many as 3 out of 4 infants with cloacal exstrophy also have spina bifida, which is when the spinal cord does not close [1]. This allows a sac of fluid, and sometimes nerves, to bulge through the opening. Spina bifida affects the nerves to the bladder, bowel and legs.

What Is the Difference Between Bladder Exstrophy and Cloacal Exstrophy?

Cloacal exstrophy is a more severe condition that involves more areas of the body [1]. It usually affects the bladder, genitals, spinal cord and bowel. Bladder exstrophy is typically just one part of cloacal exstrophy. Classic bladder exstrophy only affects the external genitals and bladder [1], which are "opened up," and the bladder is outside the body at birth.

What are the symptoms and signs of cloacal exstrophy (OEIS syndrome)?

The symptoms of OEIS syndrome are visible at birth [1]. Because the condition affects multiple systems, the physical signs are often extensive and involve the lower torso and pelvic region.

Visible Physical Signs

• Abdominal wall defect: organs in a sac coming through an opening in the baby's belly.

• Exposed organs: the bladder and intestines are open and exposed in the lower abdomen.

• Spinal abnormalities: an abnormal opening in the lower back where the spinal cord can be seen or is coming out.

• Genital differences: in babies with male genitals, the penis and scrotum may be split into two small, short halves [1]. In babies with female genitals, the clitoris and labia may be split into two halves, and there may be extra vaginas and uteruses.

Systems Affected

What causes cloacal exstrophy (OEIS syndrome) and who is at risk?

Healthcare providers do not know why some babies develop cloacal exstrophy, and there is no known way to prevent it before or during pregnancy [1]. Something happens during the first trimester that causes the cloacal membrane to tear or break apart [1].

The cloaca is the area where the reproductive system, digestive system and urinary system come together. The cloacal membrane usually separates the organs in these systems. If the membrane tears or breaks apart, the fetus's abdominal wall does not form completely. Organs do not develop as they should or may connect incorrectly, and some organs poke through an abdominal opening.

If your child has OEIS syndrome, you are not to blame. It is a condition that appears to happen without any specific cause.

What are the potential complications of cloacal exstrophy (OEIS syndrome)?

Cloacal exstrophy, part of OEIS syndrome, raises the risk of several long-term health challenges.

How is cloacal exstrophy (OEIS syndrome) diagnosed and tested?

Healthcare providers usually diagnose cloacal exstrophy during a prenatal ultrasound, and it is commonly found in the second trimester, between 17 and 30 weeks [1] [4]. They may also recommend a fetal MRI, which provides more detailed images of fetal organs [1]. These tests may reveal:

• The bladder is not filling or emptying properly

• Widely separated pelvic bones

• A small penis

• An umbilical cord that sits too low on the fetus's belly

• Abdominal wall abnormalities with a sac that bulges out and may contain organs

• An exposed spinal cord

After birth, your baby may get other imaging tests to see how severe the condition is and how well their organs work. This information helps your child's provider develop a treatment plan. These tests may include an MRI, an abdominal ultrasound and other tests [1].

How does staged surgical reconstruction treat cloacal exstrophy?

All newborns with OEIS syndrome need staged surgical reconstruction [1]. This is a series of surgeries that takes place over many years. During these surgeries, healthcare providers put your baby's organs in their proper places and close the abdominal and spinal openings.

Treatments Soon After Birth

1. Abdominal closure: fixing the bladder, placing organs back into the abdominal cavity and closing the opening in the abdomen [1] [4].

2. Colostomy: creating a temporary opening (stoma) in the abdominal wall that allows the large intestine to empty stool into a bag outside the body [1] [4]. Your baby may need a colostomy bag until they can get other surgeries.

3. Spinal repair: repairing the spinal cord and closing the back [1].

Treatments During Early Childhood

• Osteotomy: cutting and realigning the pelvic bones so the pelvis can close more easily and support the bladder as your child grows [1].

• Bladder and genital reconstruction: closing the bladder and reconstructing the genitals.

• Creating an anal opening: if there is enough large intestine, the surgeon may perform a pull-through surgery, which connects the large intestine to the rectum [1]. The surgeon then closes the stoma, and your child will no longer need a colostomy bag.

Your child will usually need other surgeries on their bladder as they grow [1].

Goals of Treatment

What is the outlook for cloacal exstrophy (OEIS syndrome)?

Your child will likely need multiple surgeries over many years, because they need to grow and develop between procedures. Improvements in surgical approaches, anesthesia and infant nutrition have helped increase cloacal exstrophy survival rates [1] [2], and your child will have a team of specialists to help manage their long-term needs.

Recovery depends on the severity of the cloacal exstrophy and how many procedures are needed. You may need special strategies for managing your child's urine and stool, and their medical team will give you a better idea of what to expect for your child's situation. With appropriate treatment, most children who have cloacal exstrophy at birth enjoy full lives, although the first years can be challenging [1].

The Care Team

A team-based approach to your child's care is very important [1] [2]. The team may include:

• Pediatric surgeon

• Pediatric urologist

• Pediatric neurosurgeon

• Genetic counselors

• Psychologist

• Pediatric gastroenterologist

• Social worker

• Physical therapist

When should you see a healthcare provider about cloacal exstrophy?

You will work closely with your child's healthcare providers to learn about and manage their care and learn how to prevent infections. As your child grows and develops, their providers may recommend additional procedures. It is important to schedule regular appointments so they can check on your child's health and plan any other necessary treatments. They can also recommend support groups [1].

Questions to Ask Your Child's Provider

• Does my child have a higher risk of any other health conditions?

• What treatment do you recommend?

• How many surgeries will my child need?

• What complications do I need to be aware of after surgery?

• What are the chances that another biological child of mine will have OEIS syndrome?

• Will my child be able to have biological children when they are older?

Conclusion

OEIS syndrome is a life-altering condition, but advances in surgery and infant care have greatly improved survival and long-term outcomes. A multidisciplinary team of specialists, including pediatric surgeons, urologists and neurosurgeons, is essential for managing the child's complex needs from birth through adulthood. Finding out that your child has a congenital condition can cause a flood of emotions, but it is important to remember that you are not to blame, and with appropriate treatment most children enjoy full lives.

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Frequently Asked Questions

What does OEIS stand for?

Omphalocele, Exstrophy of the bladder and rectum, Imperforate anus, and Spinal defects.

Is cloacal exstrophy the same as bladder exstrophy?

No. Cloacal exstrophy is more severe and usually involves the bladder, genitals, spinal cord and bowel, whereas classic bladder exstrophy only affects the bladder and external genitals. Bladder exstrophy is typically just one part of cloacal exstrophy.

How rare is this condition?

It is rare. Cincinnati Children's Hospital reports it occurs in about 1 in 200,000 to 400,000 births.

Can it be detected during pregnancy?

Yes. It is usually diagnosed during a prenatal ultrasound, and a fetal MRI may be recommended for more detail.

What causes the organs to be outside the body?

Something happens during the first trimester that makes the cloacal membrane tear or break apart, so the abdominal wall does not form completely.

Is there a cure for OEIS syndrome?

Treatment involves staged surgical reconstruction over many years. The surgeries put organs in their proper places, close the abdominal and spinal openings, and aim to protect kidney function.

How many surgeries will my child need?

Your child will likely need multiple surgeries over many years. Your child's team can tell you more about what to expect.

What is an omphalocele?

A birth defect in which abdominal organs come out through a hole near the belly button inside a membrane or sac.

What is an imperforate anus?

A condition in which the opening to the anus does not form.

Does cloacal exstrophy affect the spine?

Often. As many as 3 out of 4 infants with cloacal exstrophy also have spina bifida.

Will my child need a colostomy bag?

Your baby may need a colostomy bag until they can get other surgeries. If there is enough large intestine, a pull-through surgery may allow the stoma to be closed.

Can children with this condition walk?

Some children have problems with walking and muscle strength, which are related to the spinal defect. Ask your child's team what to expect.

Are the kidneys affected?

Cloacal exstrophy increases the risk of kidney infections, kidney stones, chronic kidney disease and kidney failure, and protecting kidney function is a main goal of treatment.

What is an osteotomy?

A procedure that cuts and realigns the pelvic bones so the pelvis can close more easily and support the bladder as your child grows.

Is cloacal exstrophy genetic?

Healthcare providers do not know why it happens, and it appears to happen without any specific cause. If you are worried about another child being affected, a genetic counselor can help.

Can it be prevented?

There is no known way to prevent it before or during pregnancy.

What is the survival rate?

Survival has improved significantly. Improvements in surgery, anesthesia and infant nutrition have increased survival rates, and a 2024 review notes that nearly all patients now survive.

Will my child have typical-looking genitals?

The genitals are often split and smaller than expected at birth. Genital reconstruction is part of the staged surgeries, and your child's team can explain what to expect.

What is the cloaca?

The area in the fetus where the reproductive system, digestive system and urinary system come together. The cloacal membrane usually separates these systems.

Can my child have biological children later in life?

Infertility is a possible complication, and it depends on the individual. It is a good question to ask your child's providers.

What is a fetal MRI?

An imaging test that provides more detailed images of a baby's organs during pregnancy.

When is the first surgery usually performed?

Treatments soon after birth include closing the abdomen, creating a colostomy and repairing the spinal opening. Your child's team will decide on timing for your child's situation.

What specialists are involved in care?

A pediatric surgeon, pediatric urologist, pediatric neurosurgeon, genetic counselors, a psychologist, a pediatric gastroenterologist, a social worker and a physical therapist.

What is spina bifida?

A condition in which the spinal cord does not close. A sac of fluid, and sometimes nerves, can bulge through the opening, and it affects the nerves to the bladder, bowel and legs.

Can the bladder be placed back inside?

Yes. Fixing the bladder, placing organs back into the abdominal cavity and closing the abdominal opening is part of the surgeries soon after birth.

What is a stoma?

An opening created surgically in the abdominal wall. In a colostomy, it lets the large intestine empty stool into a bag outside the body.

What is pull-through surgery?

A surgery that connects the large intestine to the rectum. The surgeon then closes the stoma, and your child no longer needs a colostomy bag.

Does it affect the length of the intestines?

The intestines may be shorter than expected.

Can shorter intestines cause problems?

They can affect how your body absorbs nutrients when you eat.

What is fecal incontinence?

The inability to control when you poop.

What is urinary incontinence?

The inability to control when you pee.

Are the pelvic bones affected?

Yes. The pelvic bones do not join correctly and are far apart.

Why is the back opening repaired?

Repairing the spinal cord and closing the back is one of the treatments soon after birth.

How is kidney function monitored?

Your child's providers check on your child's health at regular appointments. Ask your child's team how and how often kidney function will be checked.

Can adults with OEIS lead full lives?

With appropriate treatment, most children who have cloacal exstrophy at birth enjoy full lives. Many people need ongoing complex care into adulthood.

What imaging is used after birth?

After birth, your baby may get an MRI, an abdominal ultrasound and other tests to see how severe the condition is and how well their organs work.

Why do surgeries take years?

Your child needs to grow and develop in between procedures.

Is there a risk of kidney stones?

Yes. Cloacal exstrophy increases the risk of kidney stones.

What is a pediatric urologist?

A doctor who specializes in children's urinary and genital tracts.

What is a pediatric neurosurgeon?

A doctor who specializes in surgery on children's brain and spinal cord.

Are there support groups for parents?

Your child's care team can recommend support groups.

When is cloacal exstrophy usually diagnosed during pregnancy?

Cincinnati Children's reports it is usually diagnosed in the second trimester, between 17 and 30 weeks, on a standard ultrasound.

What are the goals of treatment?

To protect kidney function, keep urinary infection rates low, and develop strategies for peeing and pooping.

Will my child need physical therapy?

A physical therapist may be part of your child's care team, and your child's providers can tell you what support is needed.

Related Reading

• What Are Birth Defects? Symptoms, Causes, Diagnosis, and Care Explained

References

1. Cleveland Clinic. OEIS Syndrome (Cloacal Exstrophy). Cleveland Clinic Health Library. Last updated July 8, 2025. https://my.clevelandclinic.org/health/diseases/23116-cloacal-exstrophy

2. Ostertag-Hill CA, Delaplain PT, Lee T, et al. Updates on the care of cloacal exstrophy. Children (Basel). 2024;11(5):544. PMID: 38790539. https://doi.org/10.3390/children11050544

3. Costa-Roig A, Fernández-Portilla E, Domínguez-Muñóz A, et al. Cloacal exstrophy management in a low- and middle-income country (LMIC): comparative outcomes of direct versus staged closure and a multidisciplinary risk-stratified protocol. Pediatr Surg Int. 2025;41(1):160. PMID: 40483640. https://doi.org/10.1007/s00383-025-06061-3

4. Cincinnati Children's Hospital Medical Center. Cloacal Exstrophy. Cincinnati Children's Health Library. Accessed October 15, 2026. https://www.cincinnatichildrens.org/health/c/cloacal-exstrophy

Medical disclaimer

This article is for informational purposes only and is not a substitute for professional medical advice, diagnosis, or treatment. Always seek the advice of a qualified healthcare provider with any questions about a medical condition or before making decisions about treatment. Never disregard professional medical advice or delay seeking it because of something you have read here.