Pyloric stenosis refers to a narrowing of the passage between the stomach and the small intestine. The condition, which affects infants during the first several weeks of life, can be corrected effectively with surgery. The main symptom is vomiting after feedings. Other symptoms include increased appetite, weight loss, infrequent bowel movements, belching, and diarrhoea. Due to dehydration, the infant may also have fewer wet diapers.
In Finland, the analysis on pyloric stenosis got the result as 246 selected birth defects in 12,008 live births in 1999, 148 among boys and 98 among girls. Congenital heart defects (particularly septal defects) were the most common (90.8/10,000), followed by defects of the genitourinary tract (34.1/10, 000) (particularly hypospadias in boys), digestive system (23.3/10,000) and central nervous system (14.9/10,000), orofacial clefts (10.8/10,000) and Down syndrome (8.3/10,000). Completeness was satisfactory: analysis of birth certificates resulted in the addition of two birth defect cases to the registry.