Breastfeeding Rates and Growth Charts—the Zhejiang Infant Feeding Trial

A randomised control trial was undertaken in Hangzhou, China, to study the influence of the growth chart used on breastfeeding rates. Mothers with infants who were being fully breastfed at 6 weeks after birth (n = 1602) were invited to participate in the trial; 1415 agreed to participate and 1295 completed the study. Two growth charts were used, one that was heavier for the first six months of life (Chart A, n = 686) and a lighter growth chart (Chart B, n = 609). Mothers were interviewed and infants measured at 6 weeks and 3, 4, 5 and 6 months after delivery. At 6 months the full breastfeeding rates were 18.1% in the group using the heavier growth chart compared to 22.8% in the lighter growth chart group. After adjusting for potential confounders this difference remained significant (aOR 1.41, 95% confidence intervals 1.02, 1.93). These results suggest that breastfeeding rates may be influenced by the type of growth chart used. Mothers who perceive that their infants are not growing adequately ( i.e. , using the heavier charts) may introduce other foods to their infants earlier than mothers using the lighter chart. While a larger trial is required to confirm the results, in the interim it is suggested that if heavier growth charts are used, a lower percentile line could be used to assess adequacy of growth.