Is failure to thrive safe in infants?

The term describes slower-than-expected weight gain or growth over time. It may reflect difficulty feeding, an ineffective latch, frequent vomiting, swallowing problems, limited intake, or an illness that increases the infant's nutritional needs. A single measurement does not establish the problem: clinicians review the growth pattern, birth history, feeding details, wet nappies and development. Some small infants are healthy, while a downward change across growth measurements deserves attention.

Arrange a prompt appointment with the infant's doctor or child-health service. Record feeds, vomiting, stool changes and wet nappies, and bring the feeding bottle or formula details if relevant. Continue the usual breast milk or correctly prepared formula unless a clinician advises otherwise. Do not dilute formula, add cereal, or give supplements without guidance. The clinician may observe a feed, examine the infant and arrange targeted tests.

Seek urgent medical help if the infant is difficult to wake, has trouble breathing, repeatedly vomits green or bloody material, has very few wet nappies, a dry mouth, a sunken soft spot, marked weakness, or cannot keep feeds down. A fever in a very young infant also needs prompt medical advice. These signs can indicate dehydration or another illness rather than growth variation.

Ask how the growth pattern compares with earlier measurements, whether feeding technique or swallowing needs review, which warning signs require same-day help, and when weight and length should be checked again.