An inexperienced mother reports that her week-old baby has not yet had a bowel movement. What might you suspect?

In this scenario regarding a one-week-old baby who has not yet had a bowel movement, the most appropriate concern is that of imperforate anus. This condition is a congenital defect characterized by an abnormality in the anal opening, leading to a blockage and preventing the passage of stool. If a newborn fails to have a bowel movement in the first few days of life, it raises red flags for potential anatomical issues such as an imperforate anus.

While other conditions, such as meconium ileus or Hirschsprung disease, could also be considered for failure to pass stool, the distinct presentation of no bowel movement in this context combined with the specific age of the infant makes imperforate anus a plausible concern. Meconium ileus typically presents with associated digestive symptoms and is often associated with cystic fibrosis, while Hirschsprung disease usually leads to a more gradual buildup of symptoms over a week or more, often including abdominal distension and lethargy. Constipation is less likely in such a young infant since it typically refers to older infants or children with dietary influences.

Thus, in the case of a week-old infant not passing stool, imperforate anus warrants urgent evaluation due to the immediate need for surgical intervention and management of potential