Anal stenosis in 7-month-old babies may be mainly associated with congenital malformations, inflammation, anal injury, and injuries from topical medications. 1. Congenital malformation, in the embryo, the anorectal membrane between the rectum and the anal canal develops abnormally, after birth this membrane has not yet disappeared or fissure incompletely, forming anal atresia or anal stenosis (also known as small anus). Improper treatment of postnatal anal atresia can lead to anal stenosis, and sacrococcygeal developmental deformities oppressing the anorectum to cause anorectal stenosis. 2. Inflammation, such as perianal abscess, anal fistula, ulcers, syphilis, gonorrhea, lymphogranuloma and other local inflammation invades the anus, resulting in fibrous tissue proliferation, resulting in scar contracture to generate stenosis. 3. Anal injury, injury to excessive perianal tissue. Perianal skin, anal or rectal mucosa scar contracture, elasticity is weakened, resulting in stenosis. 4. Topical injury, topical corrosive drugs, injection sclerosis, necrosis agent treatment after infection necrosis can cause stenosis. After injection, local fibrin coagulation, resulting in aseptic inflammatory reaction, the formation of scar tissue after the emergence of scar anal stenosis. 5. Accidental injury and physical and chemical injury, anorectal injury due to traffic accidents, fall injury, knife injury, and strong acid and alkali injury, burns, radiation therapy injury. Due to post-injury scar formation can lead to anorectal stenosis. In addition, anal stenosis may also be associated with tumors, lasers, anal surgery, as well as such as anal fissure caused by internal sphincter spasm, long-term use of laxatives caused by the disappearance of the anorectal reflex or internal sphincter spasm. However, anal stenosis in 7-month-old babies is unlikely to be associated with these factors. It is recommended to seek active medical attention to clarify the cause of the condition.