What is the most common cause of failure to thrive?

Failure to thrive, also called faltering growth, describes slower-than-expected weight gain or growth. Some children consume too little because of feeding problems, reflux, swallowing difficulty, restrictive eating, or stress around meals. Others lose nutrients through vomiting or diarrhoea, cannot absorb food well, or need extra energy because of an underlying illness. A single small measurement does not establish the cause; clinicians look at the growth pattern, feeding history, development, family context, and examination.

Arrange a child health consultation if growth has crossed downward on the growth chart, clothes remain the same size for a long time, or feeding has become a struggle. Keep a brief record of meals, drinks, vomiting, stools, and wet nappies. Offer calm, regular meals without pressure, and do not add supplements or dilute feeds unless a clinician advises it. Bring the child’s growth records and usual foods to the appointment.

Seek urgent medical help if a child is unusually sleepy, has breathing difficulty, repeated vomiting, signs of dehydration such as very few wet nappies, or cannot keep fluids down. Prompt review is also needed for blood in vomit or stools, severe abdominal pain, or a marked change in behaviour.

Ask whether the growth pattern is concerning, how much nutrition your child needs, and whether a feeding specialist or dietitian could help. Discuss reflux, allergies, swallowing, bowel symptoms, development, and any tests that might clarify the cause.