Human oocyte quality and reproductive health

Declining female fertility is a health issue that has received broad global attention. Oocyte quality is the key limiting factor of female fertility, and key processes affecting oocyte quality involve the secretion of and response to hormones, ovarian function, oogenesis, oocyte maturation, and meiosis. However, compared with other species, the research and understanding of human oocyte quality and human reproductive health is limited. This review highlights our current understanding of the physiological factors and pathological factors related to human oocyte quality and discusses potential treatments. In terms of physiology, we discuss the regulation of the hypothalamic-pituitary-gonadal axis, granulosa cells, key subcellular structures, maternal mRNA homeostasis, the extracellular matrix, the maternal microenvironment, and multi-omics resources related to human oocyte quality. In terms of pathology, we review hypothalamic-pituitary-gonadal defects, ovarian dysfunction (including premature ovarian insufficiency and polycystic ovary syndrome), human oocyte development defects, and aging. In terms of the pathological aspects of human oocyte development and quality defects, nearly half of the reported pathogenic genes are involved in meiosis, while the remainder are involved in maternal mRNA regulation, the subcortical maternal complex, zona pellucida formation, ion channels, protein transport, and mitochondrial function. Furthermore, we outline the emerging scientific prospects and challenges for future explorations of the biological mechanisms behind infertility and the development of clinical treatments. This review seeks to deepen our understanding of the mechanisms regulating human oocyte quality and to provide novel insights into clinical female infertility characterized by defects in oocyte quality and oocyte development.