Potential Role of Prebiotics and Probiotics on Oocyte Quality, Embryo Development, Endometrial Health, and Fertility Outcomes in Assisted Reproductive Technologies

Assisted reproductive technologies (ART) have transformed infertility treatment over recent decades, yet success rates remain inconsistent. Beyond the established embryological and hormonal determinants, emerging research identifies the human microbiome—particularly gut and reproductive tract communities—as a critical regulator of reproductive efficiency. The gut microbiota influences endocrine balance, metabolic signaling, and immune homeostasis, all of which have a direct impact on oocyte maturation, embryo viability, and endometrial receptivity. Dysbiosis, characterized by the depletion of beneficial lactobacilli and an increase in pro-inflammatory bacterial taxa, has been associated with oxidative stress, reduced oocyte competence, and implantation failure. In contrast, a balanced microbiota supports follicular health and hormonal coordination. Prebiotic and probiotic interventions may enhance reproductive outcomes through several complementary mechanisms. By restoring a Lactobacillus-dominant microbial profile, they help stabilize the reproductive tract ecosystem, reinforce epithelial and immune barrier function, and limit the overgrowth of potentially pathogenic species. These changes reduce local inflammation and oxidative stress while promoting the secretion of antimicrobial peptides and bacteriocins that maintain tissue integrity. Collectively, these microbiome-mediated effects can contribute to improved follicular fluid homeostasis, enhanced oocyte competence, better early embryo development, and ultimately higher ART success rates. In conclusion, modulation of the gut-reproductive axis through targeted probiotic or prebiotic therapy represents a promising biological adjunct to assisted reproduction. Further mechanistic studies and large-scale randomized trials are warranted to validate its clinical applicability and optimize therapeutic regimens.