What does failure to thrive mean in infants?

Clinicians use this term when an infant is not following their expected growth pattern. They look at weight, length and head growth over time rather than one measurement alone. A change across growth-chart lines, feeding difficulty, frequent vomiting, swallowing problems, or reduced alertness can provide useful clues. The phrase describes a growth concern; it does not identify one single cause or mean that a parent has done something wrong.

Arrange an assessment with the infant’s clinician. Bring details about breast or formula feeds, preparation, feeding duration, wet nappies, vomiting, stools and any medicines. The clinician may watch a feed, review the growth record and examine the infant. Support depends on the reason found and may include feeding guidance, treatment of an underlying problem, or planned weight checks. Do not dilute formula or add supplements without clinical advice.

Seek urgent medical help if the infant is difficult to wake, has trouble breathing, has blue or grey lips, repeatedly vomits green fluid, shows signs of dehydration, or cannot keep feeds down. Prompt assessment is also needed when feeding suddenly becomes much worse or the infant seems markedly less responsive. Keep offering feeds as advised while arranging help, but do not delay urgent care.

Ask which growth measurements are concerning, whether feeding technique or milk intake needs review, what symptoms should be recorded, and when the next weight check should happen. You can also ask which signs would require same-day care and who to contact if feeding becomes difficult.