Background:
Systematic reviews were conducted as part of the U.S. Department of Agriculture and Department of Health and Human Services Pregnancy and Birth to 24 Months Project.
The goal of this systematic review was to examine the following question: What is the relationship between timing of introduction of complementary foods and beverages (CFB) and developmental milestones?
Complementary feeding is the process that starts when human milk or infant formula is complemented by other foods and beverages, beginning during infancy and typically continuing to 24 months of age. CFB were defined as foods and/or beverages other than human milk or infant formula (liquids, semisolids, and solids) provided to an infant or young child to provide nutrients and energy.
Conclusion Statement:
There was insufficient evidence to draw a conclusion about the relationships between timing of introduction of CFB and developmental milestones.
Grade: Grade Not Assignable
Methods:
This systematic review was conducted by a team of staff from the Nutrition Evidence Systematic Review in collaboration with a Technical Expert Collaborative.
Literature search was conducted using 4 databases (PubMed, Cochrane, Embase, and CINAHL) to identify articles that evaluated the intervention or exposure of timing of CFB introduction and the outcomes of developmental milestones. A manual search was conducted to identify articles that may not have been included in the electronic databases searched. Articles were screened by two analysts independently for inclusion based on pre-determined criteria.
Data extraction and risk of bias assessment were conducted for each included study, and both were checked for accuracy. The body of evidence was qualitatively synthesized to inform development of a conclusion statement(s), and the strength of evidence was graded using pre-established criteria evaluating the body of evidence on risk of bias, adequacy, consistency, impact, and generalizability.
Summary of the Evidence:
Three articles (one RCT; two observational studies) met criteria for inclusion that examined timing of introduction of CFB and developmental milestones
The RCT found no associations between timing of CFB and receptive or expressive language or fine- or gross-motor milestones at 30-35 months
One observational study reported that earlier CFB introduction at 4 months relative to at/after 6 months was associated with earlier gross-motor milestone achievement (e.g., crawling, cruising, and walking) via maternal report by 18 months of age
The other observational study found no associations between timing of CFB introduction and reading or math skills at 4 years of age
The relationship between timing of introduction of CFB and developmental milestones may be influenced by a number of related factors, such as birth weight, current weight, type of early feeding (breast, formula, or mixed feedings), types and/or amount of human milk and CFB consumed, and the interval between exposure and outcome assessment
The ability to draw conclusions was restricted by an inadequate amount of or limited evidence with the potential for reverse causality, and wide variation in study design, type and age of outcome assessment, exposure assessment, and reported results.