An anorectal malformation is an anomaly in the formation and/or position of the anus and rectum, the outlet for the digestive tract. This birth defect is relatively rare, occurring in approximately one of every 5,000 births and tending to be more common in males. Treatment involves surgery to correct the malformation, and in some cases, multiple surgical procedures may be necessary to address the issue. The condition is usually identified shortly after birth because it tends to be visually obvious.
This birth defect happens when errors occur during fetal development and the anus and rectum fail to separate from the urinary tract and genital tract. In some cases, there appears to be a genetic component. Anorectal malformation is linked with several genetic diseases and in families with a history of this condition, there is an increased risk of developing it. In other cases, it seems to be random in nature and there are no identifiable risk factors.
In a baby with anorectal malformation, the anus will be further forward than expected. Sometimes the gut empties into the genitourinary tract. Babies can also have imperforate anus, where there is no outlet to the outside, a condition requiring immediate surgery to create an outlet for feces before complications develop as a result of an inability to defecate. Treatment involves plastic surgery to reposition the rectum and anus, and in the case of imperforate anus, to build a new anus so the baby can express feces.
The complexity of surgery varies, depending on the nature of the case. Sometimes, a baby needs to be fitted with a colostomy and a series of surgeries is performed to move the rectum and anus, repair problems, and rebuild the rectum. In other cases, the surgery is relatively simple and only a single procedure is needed to reposition the rectum and correct the anorectal malformation.
Sometimes, an anorectal malformation is subtle and may not be noticed immediately after birth. In these cases, problems may develop in the days immediately following birth. Pediatricians can evaluate infants who appear to be having difficulties with their intestinal tracts to look for signs of congenital anomalies that might be responsible for the problem, and can refer their patients to a surgeon if surgery appears necessary. People with this condition generally do not need follow-up support once their surgeries are complete and they are defecating normally. If the condition is accompanied with other digestive tract abnormalities, however, the patient may need a special diet or other measures.