Objective: The short duration or lack of breastfeeding has been associated with maternal obesity. The purpose of this study was to systematically review prospective studies that assessed the effect of maternal obesity on lactation. Methods: A search of studies was conducted in Pubmed, these included prospective studies on maternal obesity and initiation, intention and duration of breastfeeding: 653 articles were found, only seven were prospective studies. After adding other studies found by hand, a total of nine studies were analyzed. Results: Three out of four papers observed a higher risk for delay lactogenesis among obese mothers, odds ratio ranging from 1.02 to 1.10. The study assessing the initiation of lactation showed that non-obese mothers initiated lactation sooner, OR: 0.39 (95% CI: 0.25-0.62). The overall risk for cessation of breastfeeding showed that obese mothers had higher risks of early cessation, HR: 1.50 (CI 95% 1.11-2.04). In one study it was observed that obese mothers were not more likely to never breastfeed, OR = 1.56 (95% CI: 0.97-1.50). Conclusions: This review shows that in prospective studies, obese mothers are more likely to have delayed lactogenesis and reduced lactation. Therefore, weight control and breastfeeding promotion should be reinforced before and during pregnancy. In overweight and obese mothers, breastfeeding should be closely monitored after birth.