Figure 1.

The initial search identified 2595 articles. A total of 1683 duplicate articles were removed. From the remaining articles 702 articles were excluded because they did not measure the nutrients of interest or they were not original articles. The remaining 210 full-text articles were reveiewed and 147 were excluded because the breastmilk analyzed was from mothers delivering at term. The remaining 63 articles were examined, and an additional 36 were excluded because the methods of collection did not meet inclusion criteria. In total, 27 articles met inclusion criteria.