ABSTRACT
OBJECTIVE: To use a quantitative approach to evaluate the literature for quantity, quality, and consistency of studies of maternal and infant characteristics in association with breastfeeding initiation and continuation, and to conduct a meta-analysis to produce summary relative risks (RRs) for selected factors. STUDY DESIGN: A systematic review using PubMed and CINAHL through March 2016 was conducted to identify relevant observational studies in developed nations, reporting a measure of risk for 1 or more of 6 quantitatively derived, high impact factors in relation to either breastfeeding initiation or continuation. One author abstracted data using a predesigned database, which was reviewed by a second independent author; data evaluation and interpretation included all co-authors. These factors were summarized using standard meta-analysis techniques. RESULTS: Six high impact factors were identified (smoking [39 papers], mode of delivery [47 papers], parity [31 papers], dyad separation [17 papers], maternal education [62 papers], and maternal breastfeeding education [32 papers]). Summary RR from random-effects models for breastfeeding initiation were highest for high vs low maternal education (RR 2.28 [95% CI 1.92-2.70]), dyad connection vs not (RR 2.01 [95% CI 1.38-2.92]), and maternal nonsmoking vs smoking (RR = 1.76 [95% CI 1.59-1.95]); results were similar for breastfeeding continuation. CONCLUSIONS: Despite methodological heterogeneity across studies, relatively consistent results were observed for these perinatally identifiable factors associated with breastfeeding initiation and continuation, which may be informative in developing targeted interventions to provide education and support for successful breastfeeding in more families.