Gastroesophageal Reflux (GER): This is the most common cause of vomiting in infants, especially after feeding. It occurs when stomach acid flows back into the esophagus, causing discomfort and vomiting. The non-forceful nature of the vomiting and its association with feeding make GER a likely diagnosis.

Overfeeding or Incorrect Feeding Technique: Overfeeding or using an incorrect feeding technique can lead to vomiting in infants. This is because the stomach can become overwhelmed, leading to regurgitation of milk.
Milk Protein Allergy or Intolerance: Some infants may have an allergy or intolerance to proteins in milk (such as cow's milk), leading to vomiting after feeding.
Infection (e.g., Urinary Tract Infection, Gastroenteritis): Although less common in this age group without other symptoms, infections can cause vomiting in infants.

Pyloric Stenosis: Although typically presents with forceful vomiting, it's crucial not to miss this condition. Pyloric stenosis is a narrowing of the pylorus, the opening from the stomach into the small intestine, which can lead to severe vomiting and dehydration if not treated.
Intestinal Obstruction: Any condition that causes a blockage in the intestines can lead to vomiting. This is a medical emergency and requires immediate attention.
Congenital Heart Disease: Some congenital heart defects can present with feeding difficulties and vomiting due to decreased cardiac output and increased energy expenditure during feeding.

Metabolic Disorders: Certain metabolic disorders can cause vomiting in infants, such as disorders of amino acid metabolism.
Food Allergies (other than milk protein): While less common, allergies to other foods can cause gastrointestinal symptoms, including vomiting.
Anatomical Abnormalities (e.g., Esophageal Atresia, Tracheoesophageal Fistula): These conditions are typically identified shortly after birth but can occasionally present later with vomiting among other symptoms.