Background/Objectives: Infertility in both men and women can be significantly influenced by oxidative stress (OS), which occurs due to an imbalance between reactive oxygen species (ROS) and the body’s antioxidant defenses. In women, OS disrupts oocyte maturation, implantation, and the viability of the embryo; in men, it impairs sperm quality, reduces motility, and damages DNA integrity. This review explores existing research on how dietary and lifestyle interventions can reduce OS and enhance reproductive health outcomes. Methods: We conducted a comprehensive review of clinical, translational, and molecular studies exploring the mechanisms by which OS affects fertility, as well as the efficacy of nutritional and behavioral strategies. The interventions evaluated include weight management, regular exercise, micronutrient supplementation, antioxidant-rich diets, smoking and alcohol cessation, and stress-reduction techniques. Results: Specific dietary components such as zinc, selenium, vitamins C and E, and polyphenols have been found to neutralize reactive oxygen species (ROS) and enhance gamete function. OS is additionally reduced through lifestyle modifications, including minimizing harmful exposures, managing stress, and participating in moderate physical activity. Biomarkers such as ROS levels, total antioxidant capacity, 8-OHdG, and DNA fragmentation index are essential for assessing the effectiveness of interventions. Conclusions: Fertility in both sexes can be improved, and oxidative stress significantly reduced, through a multimodal approach incorporating dietary and lifestyle changes. There are encouraging opportunities to improve reproductive health through customized approaches that are informed by biomarker profiles. To incorporate these treatments into regular fertility care, future studies should concentrate on standardized procedures and long-term results.

Several reproductive issues in both men and women are caused by changes in the pulsatile secretion of luteinizing hormone (LH) and follicle-stimulating hormone (FSH). For males to sustain spermatogenesis and Leydig cell function, and for females to ensure orderly folliculogenesis, ovulation, and ovarian steroidogenesis, precise coordination of LH and FSH secretion is necessary. Pituitary responsiveness, the frequency or amplitude of gonadotropin-releasing hormone pulses, or the dysregulation of feedback signals mediated by sex steroids and inhibins all disrupt the balance between LH and FSH secretion. Oligozoospermia, luteal-phase abnormalities, anovulation, or complete spermatogenic failure are possible clinical signs of these alterations. In addition to functional neuroendocrine disturbances, emerging genetic and epigenetic evidence, including pathogenic variants in genes such as gonadotropin-releasing hormone receptor, kisspeptin, kisspeptin receptor, luteinizing hormone beta subunit, follicle-stimulating hormone beta subunit, follicle-stimulating hormone receptor, and luteinizing hormone/choriogonadotropin receptor, has highlighted the role of inherited and acquired molecular defects in disrupting gonadotropin regulation. This narrative review synthesizes contemporary mechanistic, clinical, translational, and genetic evidence elucidating how dysregulated secretion of LH and FSH contributes to reproductive dysfunction. The molecular processes that regulate gonadotropin synthesis and release, as well as neuroendocrine regulation, gene-level determinants of hypothalamic–pituitary–gonadal (HPG) axis dysfunction, and the clinical phenotypes that result from their disruption, are all given special attention. We conclude with a discussion of new treatment strategies that target local intragonadal regulators to enhance gametogenic capacity, modulate gonadotropin signaling, or restore physiological gonadotropin-releasing hormone (GnRH) pulsatility, with consideration of how genetic insights may inform personalized therapeutic approaches.

Ovarian function relies on a network of well-coordinated molecular mechanisms that regulate follicular development, oocyte maturation, ovulation, and corpus luteum function. When these processes are disrupted, infertility can result. Extracellular matrix (ECM) remodeling represents a central regulatory component in these processes and is essential for follicle rupture and oocyte release. This mechanism involves metalloproteinases (MMPs), mainly MMP-2 and MMP-9, which degrade the ECM and allow the necessary structural changes. Other ECM-modulating proteases, such as ADAM and ADAMTS families, also contribute to this process. Their activity is tightly regulated by tissue inhibitors of metalloproteinases (TIMPs), ensuring that tissue remodeling occurs in a controlled manner. Disruption of the balance between MMPs and TIMPs increases the risk of infertility-related conditions such as polycystic ovary syndrome (PCOS), endometriosis, luteinizing hormone (LH) deficiency syndrome, and ovarian aging. In addition to the ECM, other factors, including intracellular signaling pathways, oxidative stress (OS), and mitochondrial function, contribute to ovarian physiology and directly affect oocyte quality and viability. This narrative review focuses on the molecular mechanisms governing ovarian function, with particular emphasis on the remodeling of the ECM by MMPs during ovulation, and examines how their disorders contribute to infertility. A deeper understanding of these mechanisms may lead to the identification of new therapeutic targets and the improvement of assisted reproduction outcomes.

Adipocytes produce the hormone leptin, a hormone that links energy availability to reproductive function by permitting activation of the hypothalamic–pituitary–gonadal (HPG) axis. Loss-of-function mutations in the long leptin receptor isoform (LEPRb) disrupt intracellular signaling pathways, including the Janus kinase 2 (JAK2)/signal transducer and activator of transcription 3 (STAT3), phosphoinositide 3-kinase (PI3K), and mitogen-activated protein kinase (MAPK) pathways, resulting in central leptin resistance and impaired neuroendocrine control of reproduction. Evidence from human monogenic obesity syndromes, animal models, and neuroendocrine studies indicates that LEPRb mutations disrupt hypothalamic circuitry upstream of gonadotropin-releasing hormone (GnRH) neurons, impairing GnRH pulsatility and leading to hypogonadotropic hypogonadism (HH) and infertility. This review synthesizes molecular, translational, and clinical data highlighting the central role of kisspeptin-mediated signaling in leptin-dependent reproductive regulation. Current therapeutic limitations are discussed alongside emerging approaches, including kisspeptin-based therapies and receptor-targeted strategies. Elucidating how LEPRb dysfunction disrupts metabolic–reproductive integration may provide insights into both rare monogenic conditions and common obesity-associated reproductive dysfunction.

Background: Recurrent implantation failure (RIF) remains one of the most challenging presentations in assisted reproductive technology and is characterized by failure to achieve clinical pregnancy despite the transfer of multiple good-quality embryos. Advances in embryo selection and preimplantation genetic testing have highlighted the contribution of endometrial factors to a substantial proportion of otherwise unexplained implantation failures. Methods: This narrative review summarizes current evidence regarding endometrial receptivity, the principal endometrial mechanisms implicated in RIF, contemporary diagnostic approaches, and available therapeutic strategies. Electronic literature searches were conducted using PubMed/MEDLINE, Scopus, ScienceDirect, and the Cochrane Library for publications available up to June 2026. Results: Anatomical, inflammatory, temporal, hormonal, immunological, and vascular endometrial causes of RIF can all be broadly categorized. Progesterone resistance, impaired decidualization, chronic endometritis, microbiome dysbiosis, displacement of the window of implantation, and immune dysregulation represent proposed mechanisms contributing to implantation failure in selected patients. Diagnostic evaluation is most effective when performed using a stepwise approach that prioritizes clinically actionable findings and avoids indiscriminate testing. Management primarily focuses on optimizing hormonal support, whereas immunomodulatory and antithrombotic therapies should be reserved for carefully selected patients. Emerging approaches, including granulocyte colony-stimulating factor, platelet-rich plasma, and microbiome-directed therapies, have shown promising preliminary results in selected patient populations; however, further validation is required. Conclusions: RIF is best regarded as a heterogeneous clinical outcome rather than a single disease entity, reflecting multiple disturbances in endometrial receptivity. Overall, current evidence supports a mechanism-informed approach that integrates targeted diagnostics with individualized, evidence-based therapeutic strategies.

Spinal cord injury is strongly associated with male infertility, traditionally attributed to erectile and ejaculatory dysfunction. However, accumulating evidence demonstrates that infertility in this population extends beyond neurogenic impairment and involves profound biochemical and molecular alterations within the male reproductive system. The objective of this review is to synthesize current evidence on the role of oxidative stress, inflammation, and sperm DNA damage as central mechanisms driving impaired fertility in men with spinal cord injury. A comprehensive evaluation of clinical and experimental studies indicates that seminal plasma in affected individuals is characterized by elevated reactive oxygen species, reduced antioxidant capacity, and a pro-inflammatory cytokine profile, including increased levels of tumor necrosis factor alpha, interleukin 6, and interleukin 1 beta. These alterations are closely linked to leukocytospermia, mitochondrial dysfunction, and disruption of the blood–testis barrier, creating a toxic microenvironment that compromises sperm function. As a consequence, spermatozoa exhibit reduced motility, impaired membrane integrity, and significantly increased DNA fragmentation and chromatin abnormalities. Elevated sperm DNA damage has been consistently associated with poor fertilization outcomes, reduced embryo quality, and increased risk of pregnancy loss in assisted reproductive settings. Importantly, these molecular defects persist even when sperm are retrieved using advanced techniques such as electroejaculation or surgical extraction, highlighting the need for targeted therapeutic strategies. Interventions aimed at reducing oxidative stress and modulating inflammation, including antioxidant supplementation and advanced sperm selection methods, show promise but remain insufficiently standardized. Future research should focus on the development of personalized approaches integrating molecular diagnostics and targeted therapies to improve reproductive outcomes in this population. Collectively, this review reframes spinal cord injury-related infertility as a complex inflammatory and oxidative disorder and underscores the importance of addressing sperm DNA integrity in clinical management.