Cannabinoids across the reproductive continuum: Fertility, implantation, early pregnancy and lactation

Research Objective: This review aimed to summarize the impact of cannabinoids on the reproductive continuum, including male and female fertility, embryo implantation, early pregnancy, and lactation. Methodology: A comprehensive narrative literature review was conducted using the PubMed database to identify relevant studies focusing on the effects of endogenous, plant-derived, and synthetic cannabinoids on reproductive physiology and outcomes. Main Conclusions: The endocannabinoid system plays a crucial regulatory role throughout reproductive lifespan. In males, cannabis use is linked to reduced sperm concentration, altered morphology, and potential disruption of the hypothalamic–pituitary–gonadal axis. In females, cannabinoids may inhibit gonadotropin-releasing hormone, disrupt ovulation, and impair oocyte competence. Furthermore, they can interfere with endocannabinoid signaling essential for embryo implantation, potentially increasing early pregnancy loss and placental issues. During lactation, cannabinoids can transfer to breast milk, raising neonatal exposure concerns and potential neurodevelopmental effects, yet clinical data remain inconsistent. Application of the Study: These findings stress the reproductive risks associated with cannabinoid use, advocating a precautionary approach for individuals planning conception, during pregnancy, and lactation. There is a compelling need for well-designed human studies to clarify long-term reproductive and developmental consequences of cannabinoid exposure. Originality/Novelty: This review integrates evidence across the reproductive continuum—a rarely covered approach—highlighting knowledge gaps and advocating for standardized frameworks in cannabinoid research and public health recommendations.