Cetin I, Taricco E, Mandò C, et al. - Given the importance of glucose and oxygen availability for fetal growth and well being in a healthy pregnancy, but lack of knowledge as to how substrate delivery and fetal uptake are influenced in human pregnancy complicated by fetal growth restriction (FGR) led researchers to perform this study wherein they point out that the human FGR fetus has a strikingly decreased umbilical uptake of both oxygen and glucose. They analyzed 30 healthy term and 32 FGR human pregnancies. They noted significantly lower umbilical blood flow in FGR pregnancy but not when normalized for fetal body weight. Umbilical oxygen delivery and uptake were significantly lower in FGR pregnancy, both as absolute values and normalized for fetal body weight. In FGR pregnancy, they found significantly increased glucose/oxygen quotient while significantly reduced glucose clearance. In FGR pregnancy, compensatory mechanisms are triggered by the human fetus to decrease its metabolic rate, matching the proportion of substrate consumption compared with oxygen delivery as a survival strategy during complicated pregnancy.