How babies grow

The United States Centers for Disease Control (CDC) recently recommended a long-awaited change in the way we track babies’ growth.

For years, US pediatricians and family docs have used growth charts from the CDC for monitoring infants and children. These charts were based on cross-sections of small segments of the (largely formula-fed) US population. They are considered “references” rather than “standards”, even though it is easy for doctors and parents to assume there is something wrong if a baby’s growth doesn’t follow the expected curve. And because breastfeeding babies’ growth patterns differ from formula-fed babies, this situation made it possible for some babies to be given formula unnecessarily for “poor growth”.

Now an expert panel convened by the CDC, National Institutes of Health (NIH) and American Academy of Pediatrics (AAP) recommends that clinicians use World Health Organization (WHO) growth charts for infants up to two years of age. The WHO growth charts are based on consecutive measurements over time of healthy breastfeeding babies around the world (almost 19,000 measurements in more than 800 babies). These charts serve as a standard rather than a reference for growth, since these were carefully selected healthy infants and, as the CDC’s statement points out, breastfeeding is the optimal form of infant feeding. Because of the variation in babies’ growth and the lack of correlation with poor outcomes, care providers are advised to “accept” growth within 2 standard deviations from the norm, i.e., between approximately the 3rd and 97th percentiles rather than 5th and 10th.

The CDC statement takes care to point out that for babies whose growth deviates from the standard, “clinicians need to carefully assess general health issues and ensure appropriate management of lactation. Only if there is evidence of lactation inadequacy should they consider supplementation with formula.” It also reminds us, as always, to be mindful of environmental and social factors contributing to challenges in growth.

The bottom line: this is a welcome — some might say overdue — affirmation of breastfeeding as the standard for infant nutrition.

Kimberly Lee is a neonatologist and member of the Academy of Breastfeeding Medicine.

Posts on this blog reflect the opinions of individual ABM members, not the organization as a whole.