Promoting fetal stabilization during maternal hemodynamic instability or respiratory insufficiency

Fetal oxygenation is primarily determined by maternal oxygenation and uterine blood flow. Several physiologic adaptations during pregnancy support uteroplacental perfusion and, thus, fetal oxygenation. However, the physiologic changes required to sustain the metabolic demands of pregnancy may also predispose the parturient to decompensation when critical illness is superimposed upon pregnancy. In general, the critically ill gravid woman is treated similarly to the nonpregnant adult, with the exception of accomodating the physiologic changes of pregnancy and evaluating fetal well-being. An overview of the physiology of fetal oxygenation, impact of critical care interventions upon the fetus, and evaluation of the fetus is provided.