Anorectal Malformation
CHOC pediatric general surgeons are experts in repairing anorectal malformations, including imperforate anus, in children—even newborn babies.
8 min read
Make an Appointment
Call today to schedule an appointment with one of our pediatric specialists.
Call today to schedule an appointment with one of our pediatric specialists.
What are anorectal malformations?
An anorectal malformation (ARM), commonly called imperforate anus, is a birth defect in which the anus and rectum do not develop properly, and your baby is born with a blocked or misplaced anal opening. The condition affects how your child stools through the lower digestive tract.
What causes anorectal malformations?
The direct cause of anorectal malformations is unclear. The vast majority occur by chance as a result of a defect during fetal development. Anorectal malformations are slightly more common in babies born with Trisomy 21 and Trisomy 18.
Because ARMs are not typically identified before birth, the diagnosis often comes as a surprise for families. It is also important to know that having one child with an ARM does not significantly increase the chances of having another child with the condition. In nearly all cases, ARMs do not run in families.
How do anorectal malformations occur?
Anorectal malformations typically occur when the rectum fails to separate normally from the genitourinary tract and/or ends up taking an abnormal path to the skin on the perineum. In some cases, the rectum will not reach the skin and instead connects internally to the genitourinary tract forming a fistula.
In general, the closer the rectum is to its usual position, the more likely it is that the muscles involved in bowel control will develop well. This can help a child notice when they need to have a bowel movement and make potty training easier and more successful.
What are the symptoms of anorectal malformation?
Anorectal malformations cause problems with a child’s bowel movements. Your baby may have symptoms including:
- Lack of stool
- Stool coming from the vagina
- Trouble having a bowel movement
- Chronic constipation in older children
Most anorectal malformations are found before a newborn leaves the hospital.
When should you seek help for anorectal malformation?
If your baby was not diagnosed with an ARM, but is experiencing the following symptoms, call your health care provider.
- Passes stool from her vagina
- Passes urine from the anus
- Inability to poop
- Chronic constipation
If your baby is not having any bowel movements, seek emergency care immediately.
How is anorectal malformation diagnosed?
Many babies born with anorectal malformations (ARM) also have other birth defects. When 3 or more of these are present, it is called VACTE(G)RL association. Not every child has these, but if they do, your baby may see the specialists below. VACTE(G)RL stands for:
- Vertebral (spine)
- Anorectal
- Cardiac (heart)
- Tracheo-esophageal (windpipe)
- Gynecologic (girl’s reproductive organs)
- Renal (kidneys)
- Limbs (arms and legs)
Your child’s health care provider will do a physical exam when your baby is born. The provider will examine your child’s anus to see if it is open. To better understand the anorectal malformation your child may also have imaging tests such as:
- Abdominal X-rays to take images of internal tissues, bones, and organs
- Renal ultrasound, a test that uses sound waves to make images of the kidneys, uterus and bladder.
- Spine ultrasound, a test used to examine the spine
- Babygram, which is a full body X-ray of your baby
- Echocardiogram, a test that uses ultrasound to make images of the heart.
How is anorectal malformation treated?
Treatment will depend on your child’s symptoms, age and general health. It will also depend on the severity of the condition.
Most babies with ARM will need surgery to correct the problem. The type and number of surgeries your child needs will vary, depending on his or her condition.
In addition, children with anorectal malformation receive specialized, multidisciplinary care by the CHOC Colorectal-Bowel Management Program.
What are the different types of anorectal malformations?
Anorectal malformations (ARMs) include a wide range of conditions that affect how the rectum and anus develop. They can range from mild forms, with anatomy that is close to typical, to more complex malformations. While some ARMs include an imperforate anus, not all do.
Doctors classify ARMs based on a child’s specific anatomy. Although older terms such as “high” and “low” malformations are sometimes used, many surgeons now prefer more detailed descriptions because they provide a clearer picture of the condition. The most widely used system today is the Krickenbeck Classification, which groups ARMs into several major clinical types.
Common types of anorectal malformations
There are several types of anorectal malformations, each with its own unique characteristics. Our team carefully evaluates your child’s anatomy to recommend the safest and most effective treatment plan.
A rectoperineal fistula is generally considered one of the mildest types of anorectal malformation in both males and females. In this condition, the rectum extends to the skin of the perineum, though it may not be completely centered within the muscle complex that supports bowel control. The mildest form is called anal stenosis, in which the rectum and anus develop in the expected location, but the anal opening is unusually narrow
In girls with an anorectal malformation, the rectum may open at different points between the expected location of the anus and the vaginal opening. The most common form is called a rectovestibular fistula. This means that the rectum opens into the vestibule, a small area of the external genital region located just behind the vaginal opening.
Most babies with these defects will pass some meconium externally soon after birth. Female infants born with these types of defects may or may not require colostomy near the time of birth. That decision is usually made after the surgeon examines the newborn baby and develops a treatment plan. Less commonly female infants may have a cloaca, or persistent cloaca, which is discussed in a little more detail below.
Cloacal malformations are rare and complex birth defects that affect the urinary, reproductive, and digestive systems. In babies born with a cloacal malformation, these systems come together into a single opening instead of separate openings.
Because the digestive tract cannot function normally, most babies with a cloacal malformation require a colostomy shortly after birth. In some cases, the condition can also affect how urine drains from the body. Fluid may collect in the vagina, a condition called hydrocolpos, which may require drainage and careful monitoring.
Because cloacal malformations are uncommon and highly specialized, treatment is best provided by an experienced multidisciplinary care team. At Rady Children’s Health in Orange County, pediatric colorectal surgeons, urologists, gynecologists, and other specialists work together to provide coordinated care and advanced surgical treatment tailored to each child’s needs.
Other types of anorectal malformations in males
In males, anorectal malformations (ARMs) may involve a connection between the rectum and the urinary tract. These include rectourethral prostatic, rectourethral bulbar, and rectovesical defects, where the rectum connects to the urethra near the prostate, the urethra closer to the penis, or the bladder.
In these cases, the rectum does not reach the skin in the perineal area, so stool (meconium) cannot pass through a normal opening after birth. Because of this, a colostomy is typically needed shortly after the baby is born.
How are anorectal malformations treated?
Treatment will depend on your child’s symptoms, age and general health. It will also depend on the severity of the condition.
Most babies with anorectal malformations will need surgery to correct the problem. The type and number of surgeries your child needs will vary, depending on his or her condition.
Depending on your child’s needs, additional specialists may become involved in their care:
- Neurosurgery/Spine Specialists: Spine imaging may identify differences in the spine or spinal cord that require monitoring or treatment. Early detection can help protect mobility, as well as bladder and bowel function.
- Cardiology and Cardiac Surgery: Some children with ARM are born with heart defects. While many are mild, others may require additional testing, monitoring or surgery.
- Tracheoesophageal Specialists: Imaging may be performed to look for conditions involving the esophagus and trachea. If present, these conditions typically require early treatment to support safe feeding and breathing.
- Urology: Some children with anorectal malformations have associated urinary tract or reproductive differences. A urologist can evaluate these findings and help determine if and when treatment is needed.
- Gastroenterology (GI): GI specialists help manage constipation, bowel control, and other digestive concerns, often working with families to develop a personalized bowel management plan.
- Genetics: If multiple congenital differences are present, genetic testing and counseling may help identify an underlying syndrome and guide future care.
Learn more about anorectal malformation treatments and surgery.
All of the above specialists can be found at Rady Children’s Health in Orange County. These visits can be coordinated through the Rady Children’s Health Orange County Colorectal and Urogenital Center. We can be contacted at [email protected] or by calling (714)-509-4099.