Metabolic stress during high-risk pregnancies is defined as a placental energy homeostasis disruption. With this, we examined the mitochondrial structure, respiration, and energy metabolism of the placenta in the context of preeclampsia, gestational diabetes mellitus, and intrauterine growth restriction. Since the analyses showed extreme mitochondrial ultrastructural anomalies, loss of respiration, and efficiency of the coupling and ATP synthesis processes in cross-sectioned high-risk placentas, we are addressing this phenomenon in the context of redox imbalance and the increased compensatory glycolytic metabolism. During this research, multidimensional correlation and predictive modeling helped us examine the continuum of the severity of adverse outcomes of pregnancies and pinpoint loss of energy metabolism and mitochondrial dysfunction. This abhorrent phenomenon of placental energy metabolism and increased glycolytic metabolism is a key characteristic of high-risk pregnancies. This research emphasizes the pragmatic nature of placental energy metabolism as a focus for innovative diagnostic and therapeutic strategies in obstetric care. The research results also provide a basis for risk stratification based on quantifiable placental maladaptation biomarkers.