In vivo gamete toxicology in the context of in vitro fertilization: a narrative review

In vitro fertilization (IVF) as a clinical method to surmount infertility has existed since the 1970s, and yet fertilization, embryo development, pregnancy, and live birth rates remain unacceptably low. Although a multitude of factors may contribute to stagnated success despite substantial advances in basic and applied IVF sciences, gamete quality is inarguably integral to IVF treatment success rates. In this review, the investigators explored the role of environmental toxicology in impairing in vivo fertility and gamete quality before starting IVF, which may influence downstream IVF treatment success. In vivo, contaminants of interest that may affect gamete potential in the context of IVF treatment include heavy metals, perfluoroalkyl and polyfluoroalkyl substances, persistent organic pollutants, and airborne contaminants. This review aimed to provide clinicians with a comprehensive reference on potential toxicologic exposures by evaluating the existing literature on reproductive toxicology and the impact of toxic exposures on IVF clinical outcomes. It used in vitro and animal data to support correlational human studies with potential causative mechanisms and to emphasize the importance of patient evaluation of toxicologic risk.