Effect of Breastfeeding Duration on Infant Growth Until 18 Months of Age: A National Birth Cohort Study

Background
Optimal nutrition during the 1st year of life is critical to infants' healthy growth and development, and breastfeeding is a key component. However, little is known about the effect of breastfeeding duration on infant growth in Taiwan.
Purpose
The aim of this study was to examine the effect of breastfeeding duration on infant growth.
Methods
This study was based on questionnaire interviews as part of the Taiwan Birth Cohort Study, which collected information on breastfeeding duration and infant growth among infants aged from 0 to 18 months. Participants were selected from Taiwan birth registry data for 2005, using multistage stratified random sampling. The sample population was 15,868 infants ranging in gestational age between 37 and 41 weeks, excluding those with birth defects or who were hospitalized after birth. The χ2 test, analysis of variance and generalized estimating equations were used to analyze the effects of infant feeding patterns and other factors on infant growth.
Results
Breastfeeding duration had no significant effect on infant weight within the first 6 months, but after the 7th month, infants who had been breastfed for ≥6 months were lighter than infants who were not breastfed. Before 18 months of age, infants who had been breastfed for ≥6 months were slightly shorter than infants who had been breastfed for <6 months. From the 7th month onward, breastfed infants were slightly shorter than formula-fed infants.
Conclusion
These results show that different infant feeding practices correspond to differences in infant growth from 0 to 18 months, and are consistent with the World Health Organization's new growth standards.