Using the Weight and Height Percentile Calculator Tool forInfants
Doctors use growth charts and body mass index charts to compare a child’s measurements with those of other children in the same age group. By doing this, doctors can track a child’s growth over time and monitor how a child is growing in relation to other children. The growth charts your doctor uses for this purpose are a standard part of any checkup.
There are different charts for boys and girls because their growth rates and patterns differ. For both boys and girls there are two sets of charts: one for infants ages 0 to 36 months and another for children ages 2 to 20 years old. The charts show the range of heights and weights at a certain age of thousands of children from across the country.
Failure to thrive is a term commonly used to describe younger children who aren’t gaining weight normally. Children with failure to thrive usually have a weight that is below the 3rd or 5th percentile for their age and a declining growth velocity (meaning they are not gaining weight as expected) and/or a shift downward in their growth percentiles, crossing two or more percentiles on their growth charts.
If your child is just below the 3rd or 5th percentile for his weight, but he has been gaining weight normally and has a growth curve that runs parallel to the 3rd or 5th percentile and he has no other symptoms, then he probably has a normal weight. Your Pediatrician may just want to follow his growth and development at his normal well child checkups. Children with failure to thrive usually have a growth curve that over time is moving further away from the 3rd or 5th percentile or is becoming flat.
Children normally grow at a rate of about 30 g (1 ounce)/day in early infancy (birth to 3 months) and this then slows to about 20 g/day from 3-6 months and to only 12-15 g/day in later infancy (6 - 12 months). Older children grow even more slowly, with toddlers (1-3 years) growing, at about 8 g/day, and preschool age children at about 6g/day.
Many children between the ages of 6 and 18 months move up or down on their growth percentiles, but by 24 months, most children follow their growth curve and stay on the same percentile or growth channel. Still, it is usually concerning if any child, even those under 18 months, crosses more than two major percentiles downward, for example, going from the 80th percentile to the 40th (crossing the 75th and 50th percentiles), especially if he continues to have poor growth.
Among the influences on a child’s growth is his overall genetic potential for growth, which can be determined from the height of his parents, his nutritional status, and the presence of any chronic medical problems.
It is also important to look at a child’s length, in relation to his weight. Weight for length measurements can also be plotted on a growth curve and can help to determine a child’s fat stores. A child’s skin fold thickness, which can be determined by measuring their mid upper arm circumference is another measure of subcutaneous fat stores and malnutrition. Also, a child’s head circumference should be measured and followed.
There are many causes of failure to thrive. Among the ways to categorize the different conditions that cause failure to thrive and poor weight gain is to group them into conditions that cause a decreased intake of calories or an increased loss of calories. Children may also have failure to thrive from having an increased requirement for calories, such as from having a chronic infection, hyperthyroidism, congenital heart disease or chronic lung problems.
Among the conditions that can cause your child to have a diet that doesn’t provide enough calories for normal growth (decreased intake of calories) include:
anorexia or refusal to eat from chronic medical problems, such as renal disease, cancer, congenital heart disease, metabolic disorders, liver disease, HIV infection, or gastroesophageal reflux with esophagitis.
having a restrictive or fad diet
preparing formula improperly
poor milk supply for breastfeeding moms
physical abnormalities that cause difficulty swallowing (dysphagia), such as neurological disorders including cerebral palsy, trauma to the mouth, congenital abnormalities, or disorders with motility or movement of the uppger gastrointestinal tract (such as achalasia).
poverty can lead to inadaquate access to food. If you need assistance ask about getting help from WIC or other government programs.
There are many conditions that can cause an increased loss of calories including:
illnesses that can cause persistent vomiting (such as pyloric stenosis, intestinal obstructions (such as a volvulus), or a brain tumor).
conditions associated with malabsorption, usually with diarrhea which can be foul smelling and oily, such as from cystic fibrosis, allergies, celiac disease, inflammatory bowel disease, parasite infestations or other intestinal infections.
diabetes mellitus (usually includes weight loss, increased urination (polyuria) and increased thirst and drinking (polydipsia) and other metabolic conditions..
Children with failure to thrive should have a full evaluation by their Pediatrician. This will include a detailed nutritional history, including amounts and types of foods that your child eats and drinks (including the amount of juice he drinks), a description of associated symptoms (especially vomiting, diarrhea, or fever), a physical exam and a review of prior growth records to evaluate your child’s rate of growth. The rate of growth is among the most important things that will be assessed. If your child is below the 3rd or 5th percentile, but is growing normally with a growth curve that is parallel to the 3rd or 5th percentile, and he has a healthy diet and no associated symptoms, then your Pediatrician may just observe his weight gain over the next few months.
