Skip to content
How It Works
Explore
Resources Ask a Question
Who It's For
Patients
Decode results, prep for appointments, weigh options.
Caregivers & advocates
Carry the research load for someone you love.
Providers & clinicians
Resources for patients in your practice.
Log In Ask a Question
PubMed This is a summary of 8 peer-reviewed journal articles Updated
Neonatology

Identifying the Blockage: Signs, Subtypes, and Diagnosis

At a Glance

Colonic atresia in newborns is typically identified within 24 to 48 hours by signs like a swollen belly, bilious green vomiting, and failure to pass meconium. Doctors confirm the blockage and its specific subtype using a contrast enema X-ray and rule out associated conditions with a biopsy.

When a baby is born with an intestinal blockage like colonic atresia, doctors move quickly to identify the exact location and nature of the problem. While the diagnosis may feel sudden, there is a standard process that medical teams follow to ensure your baby receives the right care. (For a basic overview of the condition, see our Home Page).

Recognizing the Signs

Most babies with colonic atresia appear healthy at birth, but they begin to show signs of a blockage within the first 24 to 48 hours of life [1][2]. You may notice the following symptoms:

  • Abdominal Distension: The baby’s belly becomes visibly swollen or “puffy” because gas and fluids are trapped behind the blockage [1][2].
  • Failure to Pass Meconium: Most newborns pass their first stool (meconium) within 24 hours. A baby with atresia usually cannot pass this stool because the path is blocked [1].
  • Bilious Vomiting: The baby may vomit fluid that is bright green. This green color comes from bile, a digestive fluid, and is a major “red flag” for an intestinal obstruction [3].

How Doctors Confirm the Diagnosis

To see inside your baby’s intestines, doctors use a specialized X-ray called a contrast enema [3][4]. During this test, a liquid “dye” (contrast) is gently inserted through the baby’s rectum while X-rays are taken. This allows the radiologist to see exactly where the liquid stops.

Common findings on a contrast enema include:

  • Microcolon: Because the lower part of the colon hasn’t been used while the baby was in the womb, it may look very small or narrow [3][4].
  • Abrupt Cut-off: The dye will suddenly stop moving forward at the site of the blockage [4].
  • The “Windsock” or “Cobra Head” Sign: In certain types of atresia, the internal membrane or “web” may bulge forward under pressure from the dye, looking like a windsock or a cobra’s head on the X-ray [2][5].

Understanding the Four Subtypes

Surgeons use the Grosfeld classification to describe the four main ways the colon can be blocked [5][6]:

Type Description
Type I A thin membrane or “web” (mucosal diaphragm) blocks the inside, but the outer wall of the colon is continuous [5][7].
Type II The two healthy ends of the colon are separated by a thin, thread-like fibrous cord [6].
Type III The ends of the colon are completely separated with a V-shaped gap in the mesentery (the tissue that connects the bowel to the abdominal wall) [6].
Type IV There are “multiple atresias,” meaning there are several different blockages throughout the colon [6].

Searching for Associated Conditions

It is mandatory for doctors to check for other conditions. Most importantly, doctors will perform a rectal biopsy to rule out Hirschsprung’s disease [8][6]. Finding this early ensures the surgical team can create the best long-term plan for your baby’s recovery [5][1]. You can read more about how this affects the surgical plan in The Path to Recovery: Understanding Surgical Options.

Common questions in this guide

What are the first signs of colonic atresia in a newborn?
The most common warning signs appear within the first 24 to 48 hours of life. These include a visibly swollen or puffy belly, vomiting bright green fluid, and the baby's failure to pass their first stool.
How do doctors confirm a colonic atresia diagnosis?
Doctors typically use a specialized X-ray called a contrast enema. During this test, a liquid dye is gently inserted into the rectum, allowing radiologists to see exactly where the liquid stops and identify the specific type of blockage.
What are the different types of colonic atresia?
Surgeons use the Grosfeld classification to categorize the blockage into four types. These range from a thin internal membrane blocking the colon (Type I) to multiple different blockages spread throughout the colon (Type IV).
Why does my baby need a rectal biopsy?
A rectal biopsy is necessary to check for a related condition called Hirschsprung's disease. Ruling this out early is a mandatory step that helps the surgical team create the safest and most effective long-term recovery plan for your baby.

Questions to Ask Your Doctor

Curated prompts to bring to your next appointment.

  1. 1.Based on the contrast enema, which subtype (Type I-IV) does my baby most likely have?
  2. 2.Did the imaging show a 'windsock' or 'cobra head' sign, and what does that mean for the surgery?
  3. 3.When will the rectal biopsy be performed to check for Hirschsprung's disease?

Questions For You

Tap a prompt to share your answer — we'll use it plus this page's context to start a tailored conversation.

References

References (8)
  1. 1

    Colonic atresia: a rare entity in the newborn. A six-case report and a bibliographic review.

    Cabrera Valerio C, Díaz Z, Alcántara E, Castillo R

    Cirugia pediatrica : organo oficial de la Sociedad Espanola de Cirugia Pediatrica 2021; (34(2)):74-78.

    PMID: 33826259
  2. 2

    Windsock or Cobra Head Sign: A Distinctive Imaging Sign to Differentiate Type 1 Colonic Atresia From Hirschsprung's Disease.

    Yadav R, Venkatesh S, Sudhakaran D, Ganakumar VM

    Cureus 2023; (15(3)):e36786 doi:10.7759/cureus.36786.

    PMID: 37123687
  3. 3

    Diagnostic performance and role of the contrast enema for low intestinal obstruction in neonates.

    Baad M, Delgado J, Dayneka JS, et al.

    Pediatric surgery international 2020; (36(9)):1093-1101 doi:10.1007/s00383-020-04701-4.

    PMID: 32572600
  4. 4

    Congenital multiple colonic atresias with intestinal malrotation: a case report.

    Ishii D, Miyagi H, Hirasawa M, Miyamoto K

    Surgical case reports 2020; (6(1)):60 doi:10.1186/s40792-020-00822-z.

    PMID: 32232592
  5. 5

    Colonic atresia and hirschsprung disease: a case report and review of the literature.

    Ladan A, Mahdian Jouybari R, Zareh Akbari M, Moharrami Yeganeh P

    Journal of medical case reports 2023; (17(1)):233 doi:10.1186/s13256-023-03969-z.

    PMID: 37280703
  6. 6

    Colonic Atresia: Association with Other Anomalies.

    El-Asmar KM, Abdel-Latif M, El-Kassaby AA, et al.

    Journal of neonatal surgery 2016; (5(4)):47 doi:10.21699/jns.v5i4.422.

    PMID: 27896155
  7. 7

    Colonic web in infants and toddlers: a cause of chronic bowel obstruction.

    Prasad G, Xess NG, Ranjan A, Birua H

    BMJ case reports 2025; (18(7)) doi:10.1136/bcr-2025-265216.

    PMID: 40659383
  8. 8

    Colonic atresia and Hirschsprung's disease in a neonate: A case report.

    Schermoly TP, Schropp KP

    International journal of surgery case reports 2024; (123()):110250 doi:10.1016/j.ijscr.2024.110250.

    PMID: 39265370

This page is for informational purposes only and does not replace professional medical advice. Always consult your pediatric surgeon or neonatologist regarding your baby's diagnosis and care plan.

Get notified when new evidence is published on Colonic atresia.

We monitor PubMed for new peer-reviewed studies on this topic and email a short summary when something meaningful changes.