During their first months of life, infants exhibit rapid growth and development. According to the Nemours Foundation, babies triple their birth weight in their first year of life. Because of the energy requirements to achieve that growth, infants usually develop a healthy desire for food. But certain conditions can inhibit a baby's appetite, which can lead to growth retardation, poor weight gain and developmental delays.
Acid reflux is the backward flow of stomach acid and food from the stomach to the esophagus. The acidity of the stomach contents can cause irritability, pain and decreased appetite. The symptoms of acid reflux include frequent spit ups, vomiting, cough, respiratory distress and food aversion. According to the Mayo Clinic, thickening expressed breast milk or formula and feeding the infant in an upright position can decrease the symptoms of reflux and improve feedings. Occasionally, babies need medicines to decrease the acidity of the stomach contents.
Milk Protein Allergy
Milk protein allergy is a condition in which an infant's immune system reacts against casein and whey, the proteins found in milk. This can cause pain, bloating, itching and breathing difficulty every time the infant ingests milk products. The infant loses appetite as a result of the severity of the symptoms. Avoiding milk products and feeding the infant hypoallergenic formulas can prevent the symptoms of milk protein allergy and improve the infant's appetite.
Infants lack a mature immune system, which leaves them vulnerable to serious infections. Viral and bacterial infections can cause loss of appetite in an infant. These include respiratory illnesses like pneumonia, the flu and bronchiolitis, as the baby is unable to coordinate feeding with the rapid breathing associated with those conditions. Other infections, such as urinary tract infections and gastroenteritis, can also make the infant too ill to feed.
Congenital Heart Disease
Some children are born with heart defects that prevent them from feeding adequately. These congenital heart conditions can make the infant too weak to engage in adequate feedings. Also, babies with certain congenital heart conditions can go into heart failure, leaving the heart too weak to pump blood effectively, causing a pooling of fluid in the lungs and difficulty breathing and feeding. Surgical correction of these conditions and medical management of fluid balance can help stimulate the infant's appetite, but sometimes these babies become too sick and require feeding via tubes into the stomach.