RESUMEN
Normal reference ranges for apolipoprotein A-I, apolipoprotein A-II, apolipoprotein B, total triglyceride, total cholesterol, HDL-cholesterol, LDL-cholesterol, VLDL-cholesterol + chylomicron, plasma glucose, total protein, albumin and globulin were determined from 25 fetal plasma samples between 21-39 weeks' gestation. Pure fetal blood was obtained by cordocentesis under continuous ultrasound guidance. They were referred to us for advanced maternal age and a previous chromosomal aneuploidy baby. All these biochemical parameters excepts total protein and albumin showed no change with gestational age. These normal values of fetal metabolism will improve our knowledge of physiology and help to determine the specific values of a test in fetal pathology.