ABSTRACT: The purpose of this integrative review was to identify, critique, and synthesize the maternal and neonatal evidence on the prenatal use of probiotics and prebiotics to inform perinatal health professionals. A comprehensive literature search resulted in 37 studies of prenatal probiotics and 1 on antepartal prebiotics published from 1990 through 2011 that reported maternal, fetal, and/or neonatal outcomes. The methodologic quality of the studies reviewed was high, although investigators used different probiotic combinations and inconsistently reported perinatal clinical outcomes. The extraction of perinatal outcome variables resulted in identification of 9 maternal and 5 neonatal categories. Prenatal probiotics significantly reduced the incidence of bacterial vaginosis, increased colonization with vaginal Lactobacillus and intestinal Lactobacillus rhamnosus, altered immune markers in serum and breast milk, improved maternal glucose metabolism, and reduced the incidence of gestational diabetes and preeclampsia. Antepartally, probiotics were associated with significantly higher counts of Bifidobacterium and Lactococcus lactis (healthy intestinal flora) in neonatal stool. Prenatal prebiotics significantly increased maternal intestinal Bifidobacterium. No adverse events were reported and there was evidence of safety and tolerance of prenatal probiotics and prebiotics in the scientific investigations reviewed. It is recommended that in future investigations of prenatal probiotics researchers explicitly report maternal and neonatal outcomes.