Weight faltering describes a weight pattern not a diagnosis. It represents a spectrum from what may simply be a normal variant to children with serious problems.
A weight that crosses more than two centile spaces is often the recommended threshold for concern
Causes tend to be multifactorial and often involve problems with diet and feeding behaviour that usually respond to simple targeted advice.

Plot on growth chart. Serial measurements of growth will help determine growth velocity and need for investigation (remember to make allowance for prematurity (<37 weeks), until 2 years old).

CAUSES
Organic disease is rare in otherwise asymptomatic children, but do not label everyone as feeding difficulty if there is adequate intake and child is not gaining weight. Organic causes should not be missed and should be appropriately investigated.
Inadequate intake is the most common cause. The child does not consume enough calories to support adequate growth. Contributary factors may include

? poor appetite - chronic infections, chronic fever, anaemia

? feeding problems - gastro-oesophageal reflux, cerebral palsy, cleft lip/palate

? Social/family factors - chaotic family, parental mental health, lack of knowledge, neglect

Increased calorie demand and expenditure
? Chronic infections with fever
? Surgery
? Chronic illness such as GI disorders (cystic fibrosis, inflammatory bowel disease), respiratory disorders (cystic fibrosis, severe asthma), congenital heart disease, endocrine disorders (diabetes mellitus, hyperthyroidism), renal failure
Inefficient utilisation of calories or loss of calories
? GI disorders - coeliac disease, chronic diarrhoea, chronic vomiting
? Endocrine/metabolice disorders - diabetes mellitus, hyperthyroidism, inborn errors of metabolism
? Burns, GI problems or other chronic illnesses

Developmental assesment also important area of your child 

child wth developmental delay need to be identified as soon as possible to start apropriate treatment/therapy for the best out come