Are probiotics and prebiotics safe for use during pregnancy and lactation? A systematic review and meta-analysis

Probiotic and prebiotic products are increasingly popular due to their potential health benefits, including in pregnancy where probiotic supplementation has been associated with prevention of gestational diabetes and mastitis. The incidence of adverse effects in pregnant people and their infants associated with probiotic, prebiotic and/or synbiotic product intake, however, remains unclear. The objectives of this study were to evaluate the evidence on adverse effects of maternal probiotic, prebiotic and/or synbiotic supplementation before and during pregnancy and lactation and interpret the findings to help inform clinical decision-making and care of pre-pregnant, pregnant and lactating people. A systematic review was conducted following PRISMA guidelines. Scientific databases were searched using pre-determined terms, and risk of bias assessments were conducted to determine study quality. Inclusion criteria were English language studies, human studies, access to full-text, and probiotic/prebiotic/synbiotic supplementation to the mother and not the infant. 11/70 eligible studies reported adverse effects and were eligible for inclusion in quantitative analysis, and data were visualised in a GOfER diagram. Probiotic and prebiotic products are safe for use during pregnancy and lactation. Only one study reported increased risk of vaginal discharge and changes in stool consistence (Relative Risk [95% CI]: 3.67 [1.04, 12.2]) when administering Lactobacillus rhamnosus and L. reuteri. Adverse effects associated with probiotic and prebiotic use do not pose any serious health concerns to mother or infant. Our findings and knowledge translation visualisations provide healthcare professionals and consumers with information to make evidence-informed decisions about the use of pre- and probiotics.