BackgroundProbiotics are non-invasive therapies composed of live bacteria and yeast. Administration of prebiotics improved the health status of pregnant and lactating women, as well as newborns. This review aimed to appraise the evidence concerning the effectiveness of probiotics on the mental health of pregnant women, lactating mother and the microbiota of the newborn.MethodsThis systematic review and meta-analysis ascertained quantitative studies published in Medline (PubMed), Clinical Key, EMBASE, Cumulative Index to Nursing and Allied Health Literature (CINAHL), the Cochrane Library, and Google scholar. Two authors independently screened and extracted the data from the primary studies that analysed the efficacy of probiotics on the mental health of pregnant and lactating women and the microbiota of the newborn. We adopted Cochrane Collaboration guidelines and reported using the Preferred Reporting Items for Systematic review and Meta-Analysis (PRISMA) statement. The qualities of included trials were assessed by Cochrane collaboration's risk of bias tool (ROB-2).ResultsSixteen trials comprised 946 pregnant women, 524 were lactating mothers, and 1678 were infants. The sample size of primary studies ranged from 36 to 433. Probiotics were administered as interventions, using either a single strain of Bifidobacterium or Lactobacillus or a double-strain combination of Lactobacillus and Bifidobacterium. Probiotics supplementation reduced anxiety in pregnant (n = 676, standardised mean difference (SMD) = 0.01; 95% confidence interval (CI) = -0.28,0.30,P= 0.04,I2= 70) and lactating women (n = 514, SMD = -0.17; 95% CI = -1.62,1.27,P= 0.98,I2= 0). Similarly, probiotics decreased depression in pregnant (n = 298, SMD = 0.05; 95% CI = -0.24,0.35,P= 0.20,I2= 40) and lactating women (n = 518, SMD = -0.10; 95% CI = -1.29,-1.05,P= 0.11,I2= 60%). Similarly, probiotics supplementation improved the gut microbiota and reduced the duration of crying, abdominal distension, abdominal colic and diarrhoea.ConclusionNon-invasive probiotic therapies are more useful to pregnant and lactating women and newborns.RegistrationThe review protocol was registered with PROSPERO (CRD42022372126).