Growth & Development: Growth of Term Infants

Monitoring the growth of infants and children through their childhood is an important aspect of routine pediatric care. In the United States before 2000, the NCHS growth curves were the standard growth curves used. These curves were based on the growth of children who:

1. lived in a small midwestern town,
2. were mostly Caucasian,
3. were not breastfed or were breastfed for only a short period of time, and
4. were started on solid foods in the first 1-2 months of life.

Historic NCHS physical growth percentiles for girls from birth to 36 months:

Present Breastfeeding Recommendations

The World Health Organization recommends that infants should be exclusively breastfed for 6 months with continued breastfeeding up to and beyond 2 years of age with the addition of appropriate solid foods at 6 months of age.

The American Academy of Pediatrics (AAP) states that exclusive breastfeeding is sufficient to support optimal growth and development for approximately the first 6 months of life ... and should be continued for at least the first year of life and beyond for as long as mutually desired by mother and child. Complementary foods rich in iron should be introduced gradually beginning around 6 months of age ( AAP Breastfeeding, 2005 ).

Because these curves were not representative of the growth of children of different ethnic groups living in the United States and the infants were not fed according to current recommendations, in 2000 the Centers for Disease Control and Prevention (CDC) released new growth curves ( CDC, 2000 ). The infant growth curves (shown below for girls) were developed from data collected from 1971 to 1994 by the Third National Health and Nutrition Examination Survey (NHANES III, 1988-1994), birth certificate data from Missouri and Wisconsin, head circumference at birth from the Fels Research Institute, and from the CDC Pediatric Nutrition Surveillance System. Data from very low birth weight infants (< 1500 grams) were excluded. These growth charts are representative of US ethnic and racial groups. Between 1971 and 1994 about 50% of U.S. infants were breastfed at birth and 30% were still breastfed at 3 months ( Ogden, 2002 ).

Click on the graphic to see a higher quality version.

Also available:
CDC 2000 physical growth percentiles for boys from birth to 36 months.

These are also available as PDF files:
Boys
Girls

CDC, 2000

Source: CDC

When data from the DARLING study (see next section) is plotted on these new growth curves, differences still exist. The mean weight for age of males and females in the DARLING study approximates the 50th percentile between birth and 1 month of age. Between 2 months and 5-6 months, the mean weight for age of the breastfed infants in the DARLING study is between the 50th and 75th percentile. Between 7 and 12 months of age the mean weight of the breastfed infants slowly decreases on the growth curve and reaches the 25th percentile by 12 months of age ( Dewey, 2001 ).