The present review revisits three hypothesized models that potentially could explain how prenatal maternal stress influences fetal development, birth outcomes, and subsequent developmental psychopathology. These models were mostly based on animal models, and new evidence for these models from human studies is evaluated. Furthermore, divergent trajectories from prenatal exposure to adversities to offspring affected outcomes are reviewed, including the comparison of studies on prenatal maternal stress with research on maternal substance use and maternal malnutrition during pregnancy. Finally, new directions in research on the mechanism underlying prenatal stress effects on human offspring is summarized. While it is concluded that there is abundant evidence for the negative associations between prenatal maternal stress and offspring behavioral, brain, and psychopathological outcomes in humans, there is no consistent evidence for specific mechanisms or specific outcomes in relation to stress exposure in utero. Rather, principles of multifinality and equifinality best describe the consequences for the offspring, suggesting a generic vulnerability and different pathways from prenatal adversities to developmental psychopathology, which complicates the search for underlying mechanisms. New and promising directions for research are provided to get a better understanding of how prenatal stress gets under the skin to affect fetal development.