OBJECTIVE: Preeclampsia is associated with abnormal lipid metabolism, including fatty acid metabolism. Carnitine plays an indispensable role in the oxidation of fatty acids. The aim of the study was to evaluate the possible role of abnormal fatty acid oxidation in preeclampsia by comparing plasma carnitine levels between preeclamptic and healthy control pregnant women. METHODS: Plasma concentrations of free carnitine and short-, medium-, and long-chain acylcarnitines were investigated with electrospray tandem mass spectrometry in pregnant women with preeclampsia (n = 33) and in normotensive healthy pregnant control subjects (n = 28). Excluded were multiple pregnancies and women with preexistent hypertension, diabetes, renal dysfunction, immune disease, and intrauterine fetal death. Control subjects were healthy pregnant women without hypertension or proteinuria. RESULTS: The results revealed that, except for the medium-chain plasma acylcarnitines, all plasma carnitines were significantly increased (P <..001) in the preeclamptic group (t test for unpaired samples)-. Free carnitine and the short-and long-chain acylcarnitine values were increased by approximately 50%compared with the control group. Total and short-chain plasma acylcarnitine levels were significantly correlated to diastolic blood pressure, whereas no relationship could be demonstrated between carnitine concentrations and the variables proteinuria and systolic blood pressure. CONCLUSION: The considerable increased plasma carnitine concentrations, together with the accumulation of lipids, support the role of abnormal lipid metabolism in the pathophysiology of preeclampsia. It is suggested that toxic metabolites resulting from abnormal fatty acid oxidation in the placenta contribute to the endothelial dysfunction of preeclampsia. OBJECTIVE: Preeclampsia is associated with abnormal lipid metabolism, including fatty acid metabolism. Carnitine plays an indispensable role in the oxidation of fatty acids. The aim of the study was to evaluate the possible role of abnormal fatty acid oxidation in preeclampsia by comparing plasma carnitine levels METHODS: Plasma concentrations of free carnitine and short-, medium-, and long-chain acylcarnitines were investigated with electrospray tandem mass spectrometry in pregnant women with preeclampsia (n = 33) and in normotensive healthy pregnant controls subjects (n = 28). Excluded were multiple pregnancies and women with preexistent hypertension, diabetes, renal dysfunction, immune disease, and intrauterine fetal death. Control subjects were healthy pregnant women without hypertension or proteinuria. RESULTS: The results revealed that, except for for the medium-chain plasma acylcarnitines, all plasma carnitines were significant ly increased (P <.. 001) in the preeclamptic group (t test for unpaired samples) -. Free carnitine and the short-and long-chain acylcarnitine values ​​were increased by approximately 50% compared with the control group. Total and short- chain plasma acylcarnitine levels were significantly correlated to diastolic blood pressure, no no relationship could be demonstrated between carnitine concentrations and the variables proteinuria and systolic blood pressure. CONCLUSION: The considerable increased plasma carnitine concentrations, together with the accumulation of lipids, support the role of abnormal lipid metabolism in the pathophysiology of preeclampsia. It is suggested that the toxic metabolites resulting from abnormal fatty acid oxidation in the placenta contribute to the endothelial dysfunction of preeclampsia.