Carnitine content of blood and amniotic fluid.

Free carnitine levels were determined in amniotic fluids between the 10th and 40th week of gestation. They were found to decrease significantly with gestational age. Blood levels of carnitine were lower in pregnant than in nonpregnant women. Levels were found to be higher in cord blood than in maternal blood and usually were higher in the umbilical artery than vein. Intra-arterial injection of L-carnitine into a pregnant ewe did not cause a rise in the fetal blood level of carnitine, which, in contrast to human fetal blood, contained less than half the level of carnitine in maternal blood.