My Baby Has an Imperforate Anus (Anorectal Malformation)
Medically reviewed by Dr. Michael Okonkwo, MD, FAAP · Board-Certified Neonatologist
Content reviewed against published CDC, NIH, Children's Hospital guidelines
Last reviewed:
If your baby has been diagnosed with or you suspect has an imperforate anus (anorectal malformation), here is what the evidence says.
The short answer
Imperforate anus (anorectal malformation) is a birth defect where the baby does not have a normal anal opening. The condition ranges from a simple membrane covering the anus to complex malformations where the rectum does not connect to the anus at all. It is detected on the newborn exam, often when the baby fails to pass meconium (first stool) within 24-48 hours. Low-type malformations can be repaired with a single surgery. High-type malformations typically require a staged approach, starting with a temporary colostomy. Imperforate anus can be part of the VACTERL association, so babies are evaluated for other anomalies.
Key takeaways
- Imperforate anus (anorectal malformation) is a birth defect where the baby does not have a normal anal opening. The condition ranges from a simple membrane covering the anus to complex malformations where the rectum does not connect to the anus at all. It is detected on the newborn exam, often when the baby fails to pass meconium (first stool) within 24-48 hours. Low-type malformations can be repaired with a single surgery. High-type malformations typically require a staged approach, starting with a temporary colostomy. Imperforate anus can be part of the VACTERL association, so babies are evaluated for other anomalies.
- Usually normal when: Your baby has been diagnosed and is being managed by a pediatric surgery team
- Call your doctor if: Your newborn has not passed meconium within 48 hours of birth
- Varies by age — see the age-by-age breakdown below
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Parents everywhere have the same worry. You are doing the right thing by looking into it.
What Parents Should Know
According to CDC, NIH, Children's Hospital guidelines, imperforate anus (anorectal malformation) is a birth defect where the baby does not have a normal anal opening. The condition ranges from a simple membrane covering the anus to complex malformations where the rectum does not connect to the anus at all. It is detected on the newborn exam, often when the baby fails to pass meconium (first stool) within 24-48 hours. Low-type malformations can be repaired with a single surgery. High-type malformations typically require a staged approach, starting with a temporary colostomy. Imperforate anus can be part of the VACTERL association, so babies are evaluated for other anomalies. At 0-48 hours, imperforate anus is typically diagnosed during the initial newborn physical exam when no normal anal opening is visible, or when the baby fails to pass meconium within the first 24-48 hours. Sometimes a fistula (abnormal connection) to the perineum, urethra, or vagina is present. Diagnostic imaging (ultrasound, X-ray, or MRI) helps determine the type and location of the malformation. Your baby will be evaluated for associated anomalies, particularly those in the VACTERL association (vertebral, cardiac, tracheoesophageal, renal, and limb defects). It is generally considered normal when your baby has been diagnosed and is being managed by a pediatric surgery team. However, you should contact your pediatrician promptly if your newborn has not passed meconium within 48 hours of birth.
Normal vs. Concerning
When to Seek Immediate Care
- Your newborn has not passed meconium within 48 hours of birth
- Your baby has abdominal distension with vomiting (signs of obstruction)
- You notice signs of infection at the surgical site or colostomy: redness, swelling, fever, or foul-smelling drainage
- The colostomy is not draining, looks dark or discolored, or protrudes significantly more than usual (prolapse)
- Your baby has persistent vomiting and a distended belly after repair surgery
By Age
What to expect by age
0-48 hours
Imperforate anus is typically diagnosed during the initial newborn physical exam when no normal anal opening is visible, or when the baby fails to pass meconium within the first 24-48 hours. Sometimes a fistula (abnormal connection) to the perineum, urethra, or vagina is present. Diagnostic imaging (ultrasound, X-ray, or MRI) helps determine the type and location of the malformation. Your baby will be evaluated for associated anomalies, particularly those in the VACTERL association (vertebral, cardiac, tracheoesophageal, renal, and limb defects).
2-7 days
Treatment depends on the type of malformation. Low-type (where the rectum ends close to the skin surface): a single surgery (anoplasty or posterior sagittal anorectoplasty) can create a functional anal opening. High-type (where the rectum ends far from the skin surface): a colostomy is typically created first to divert stool, allowing time for the baby to grow before definitive repair. Associated anomalies, especially cardiac and renal defects, are addressed concurrently.
1-6 months
If a colostomy was placed, your baby will have stool draining into a bag on the abdomen. Colostomy care is taught before discharge. Definitive repair (posterior sagittal anorectoplasty, or PSARP) is typically planned around 3-6 months of age, once the baby has grown. Before surgery, a distal colostogram (contrast study) is performed to map the anatomy. This period involves regular follow-up with pediatric surgery and any other specialists managing associated conditions.
6-12 months
After definitive repair, your baby begins a program of anal dilations to keep the new anal opening from narrowing (stricture). Dilations are performed by parents at home and gradually increased in size over weeks to months. This process is essential for a good outcome. Once the new anus is functioning well and dilations are complete, the colostomy is closed (usually 2-3 months after the pull-through procedure). Bowel function continues to improve over time.
1 year+
Long-term bowel function varies depending on the complexity of the malformation and the quality of the sphincter muscles. Many children with low malformations achieve normal bowel control. Those with high or complex malformations may need a bowel management program to achieve social continence. Constipation is common and may require ongoing management. With appropriate support, most children achieve a good quality of life. Follow-up with pediatric surgery continues through childhood and may extend into adolescence.
What to Tell Your Pediatrician
- Describe when you first noticed has an imperforate anus (anorectal malformation) and how it has changed over time.
- Note your baby's current age and which age-specific patterns you are seeing.
- Mention if your baby has difficulty with dilations or you are unsure about the technique.
- Mention if your child is having constipation or soiling that is not improving with current management.
- Let your doctor know if you have noticed any related concerns, such as changes in feeding, sleep, or movement patterns.
- Bring a list of any questions or observations you want to discuss at the appointment.
What Should You Do?
When to take action
- Your baby has been diagnosed and is being managed by a pediatric surgery team
- Your baby had successful surgical repair and is healing well
- You are performing anal dilations as instructed and the size is progressing appropriately
- Colostomy care is going smoothly and your baby is gaining weight
- Your child is on a bowel management program and achieving social continence
- Your baby has difficulty with dilations or you are unsure about the technique
- Your child is having constipation or soiling that is not improving with current management
- You have questions about colostomy care or upcoming surgeries
- You are concerned about your baby's growth or development
- Your newborn has not passed meconium within 48 hours of birth
- Your baby has abdominal distension with vomiting (signs of obstruction)
- You notice signs of infection at the surgical site or colostomy: redness, swelling, fever, or foul-smelling drainage
- The colostomy is not draining, looks dark or discolored, or protrudes significantly more than usual (prolapse)
- Your baby has persistent vomiting and a distended belly after repair surgery
What You Can Do at Home
- Keep track of when you notice has an imperforate anus (anorectal malformation) — noting the time of day, duration, and any triggers can help your pediatrician.
- Remember that your baby has been diagnosed and is being managed by a pediatric surgery team — this is generally within the range of normal.
- At 0-48 hours, focus on observation rather than intervention unless your pediatrician advises otherwise.
- Follow any care instructions from your pediatrician. Keep a written log of symptoms to bring to appointments.
- While monitoring at home, seek immediate care if your newborn has not passed meconium within 48 hours of birth.
Related Conditions
Delayed First Stool (Not Passing Meconium)
Most newborns pass their first meconium stool within 24-48 hours of birth. Delayed passage beyond 48 hours should be evaluated, as it can sometimes indicate conditions such as Hirschsprung disease, meconium ileus, or other bowel obstructions. Premature babies may take longer to pass meconium.
My Baby Was Diagnosed with VACTERL Association
VACTERL association is a condition where a baby is born with a combination of birth defects involving multiple organ systems. The name is an acronym: Vertebral defects, Anal atresia, Cardiac defects, Tracheoesophageal fistula, Renal anomalies, and Limb abnormalities. A diagnosis is typically made when a baby has at least 3 of these features. The cause is unknown in most cases and is usually not inherited. While the initial medical needs can be significant, many VACTERL-associated conditions are surgically correctable, and many children go on to lead healthy, active lives.
Related Resources
Frequently asked questions
Is has an imperforate anus (anorectal malformation) normal?
When should I call the doctor about has an imperforate anus (anorectal malformation)?
When is has an imperforate anus (anorectal malformation) normal?
What causes has an imperforate anus (anorectal malformation)?
What should I mention to my pediatrician about has an imperforate anus (anorectal malformation)?
Is has an imperforate anus (anorectal malformation) normal at 0-48 hours?
Is has an imperforate anus (anorectal malformation) normal at 2-7 days?
Should I go to the ER for has an imperforate anus (anorectal malformation)?
Does has an imperforate anus (anorectal malformation) go away on its own?
References
- [1]Centers for Disease Control and Prevention. Facts about Anorectal Malformations. Birth Defects, 2024. CDC
- [2]National Institutes of Health. Imperforate Anus. MedlinePlus Medical Encyclopedia, 2024. NIH
- [3]Nationwide Children's Hospital. Anorectal Malformations (Imperforate Anus). Children's Hospital
Doctor Visit Checklist
Bring this checklist to your next pediatrician visit to discuss My Baby Has an Imperforate Anus (Anorectal Malformation).
Things to mention
- Describe when you first noticed has an imperforate anus (anorectal malformation) and how it has changed over time.
- Note your baby's current age and which age-specific patterns you are seeing.
- Mention if your baby has difficulty with dilations or you are unsure about the technique.
- Mention if your child is having constipation or soiling that is not improving with current management.
- Let your doctor know if you have noticed any related concerns, such as changes in feeding, sleep, or movement patterns.
- Bring a list of any questions or observations you want to discuss at the appointment.
Observations to share
- Your baby has difficulty with dilations or you are unsure about the technique
- Your child is having constipation or soiling that is not improving with current management
- You have questions about colostomy care or upcoming surgeries
Urgent signs to report immediately
- Your newborn has not passed meconium within 48 hours of birth
- Your baby has abdominal distension with vomiting (signs of obstruction)
- You notice signs of infection at the surgical site or colostomy: redness, swelling, fever, or foul-smelling drainage
My notes
From ismybabyalright.com — free, evidence-based baby health guides
All content follows our editorial policy and is reviewed against published clinical guidelines.
2,705 evidence-based guides6 authoritative medical sources5 medical advisory board members
Related Resources
Bottom line
Most cases of has an imperforate anus (anorectal malformation) are normal. Talk to your pediatrician if your newborn has not passed meconium within 48 hours of birth.
Trust your instincts. If something feels wrong, reach out to your pediatrician. Worrying about your baby means you care — that is a good thing.
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Related Medical Concerns
Delayed First Stool (Not Passing Meconium)
Most newborns pass their first meconium stool within 24-48 hours of birth. Delayed passage beyond 48 hours should be evaluated, as it can sometimes indicate conditions such as Hirschsprung disease, meconium ileus, or other bowel obstructions. Premature babies may take longer to pass meconium.
My Baby Was Diagnosed with VACTERL Association
VACTERL association is a condition where a baby is born with a combination of birth defects involving multiple organ systems. The name is an acronym: Vertebral defects, Anal atresia, Cardiac defects, Tracheoesophageal fistula, Renal anomalies, and Limb abnormalities. A diagnosis is typically made when a baby has at least 3 of these features. The cause is unknown in most cases and is usually not inherited. While the initial medical needs can be significant, many VACTERL-associated conditions are surgically correctable, and many children go on to lead healthy, active lives.
My Baby's Head Shape Looks Abnormal
Many babies develop temporary head shape irregularities that are completely normal. A cone-shaped head from vaginal delivery reshapes within days. Mild positional flattening (plagiocephaly) from sleeping on the back is very common and usually improves with repositioning and tummy time. However, head shape changes involving ridges, a persistently bulging fontanelle, or rapid head growth changes should be evaluated to rule out craniosynostosis.
Achondroplasia (Dwarfism) in Babies
Achondroplasia is the most common form of short-limbed dwarfism, affecting about 1 in 15,000 to 40,000 births. It is caused by a mutation in the FGFR3 gene and is usually apparent at birth with characteristic features including short limbs, a larger head, and a prominent forehead. Intelligence is normal. With monitoring for specific complications and supportive care, children with achondroplasia lead full, active, and independent lives.
Adenoid Hypertrophy and Breathing
Adenoids are lymphoid tissue located behind the nose that help fight infection in young children. When adenoids become enlarged (adenoid hypertrophy), they can block the nasal airway, causing chronic mouth breathing, snoring, nasal speech, and sleep-disordered breathing. Enlarged adenoids are most common between ages 2-7 and are a leading cause of obstructive sleep apnea in young children. Treatment ranges from watchful waiting and nasal steroids to surgical removal (adenoidectomy) if breathing or sleep is significantly affected.
Adrenoleukodystrophy (ALD) in Babies
X-linked adrenoleukodystrophy (X-ALD) is a genetic disorder affecting about 1 in 17,000 newborns, caused by mutations in the ABCD1 gene on the X chromosome. It primarily affects boys and impairs the breakdown of very long-chain fatty acids (VLCFAs), which accumulate and damage the myelin sheath in the brain and the adrenal glands. The most severe form, cerebral ALD, typically affects boys between ages 4-10 with rapid neurological decline. Newborn screening now enables early detection, and hematopoietic stem cell transplant or gene therapy performed before significant brain involvement can be life-saving.